As we await the seventh (and possibly final) season of Big Bang Theory spinoff Young Sheldon, TVLine is taking stock of the prequel series’ many nods, cameos and crossovers with the mothership.
First launched in September 2017, Young Sheldon fills in the details of Dr. Cooper’s upbringing in East Texas. The story starts off in 1989, and is told from the point of view of a more mature Sheldon, “who is older now [and] seeing his parents in a different light for the first time.” This altered perspective has allowed the spinoff to chart its own path and occasionally diverge from Big Bang canon without ever disrespecting what preceded it.
Whether you’re familiar with the prequel or simply curious, the following guide provides a rundown of all the ways the single-camera offshoot has paid homage to Big Bang, provided answers to some of our lingering questions (for starters, what’s a Bazinga?!), and painted a clearer picture of Sheldon’s relationship with his family, including his ill-fated father. Also featured are multiple Easter eggs, crossovers that took place after the mothership ended, and details about Sheldon and Amy’s future that were never disclosed on BBT. We’ve also included season and episode numbers for those who want to watch (or rewatch) select episodes.
TVLine will continue to update this guide throughout Young Sheldon‘s run on CBS. In the meantime, scroll through the following list to see if you’ve caught every tip of the hat to The Big Bang Theory, then drop a comment below.
Laurie Metcalf’s real-life daughter, Zoe Perry, plays her prequel counterpart.
Lance Barber, who played Leonard’s high school bully Jimmy Speckerman, plays Sheldon’s dad.
Sheldon’s beloved grandmother was referenced throughout Big Bang‘s first eight seasons, finally appearing (in the form of June Squibb, no less!) in Season 9. Designing Women vet Annie Potts eventually took over the role, beginning with the spinoff’s third episode.
Sheldon’s father’s fate is predestined — and Young Sheldon doesn’t sugarcoat it. George’s mortality first cast a shadow over the prequel in Season 1, Episode 3, when George suffered a minor heart attack. Then in Season 4, Episode 17, Sheldon acknowledged that George was living on borrowed time.
Most recently, Season 6 of the prequel implied (in jest… we think) that George’s eventual demise would mark the eventual end of the series.
GEORGE THE ADULTERER...?
The Season 4 finale established the family patriarch’s potential fall from grace, planting the seeds for an extramarital affair between George and next-door neighbor Brenda Sparks. Seasons 5 and 6 continued to hint that something would happen, but the prequel pivoted come 13-year-old Sheldon’s spring break in Season 6, Episode 18, which is when Sheldon told Penny he walked in on his father with another woman.
Brenda’s son was established as Sheldon’s childhood bully in Seasons 3, 5 and 9 of the mothership. He made his on-screen debut in Episode 1 of the spinoff, when he taunted Sheldon with his pet chicken Mathilda. Since then, however, Billy has been portrayed as more of a nuisance than a tormentor, and hasn’t given the future physicist reason to add him to his all-time enemies list… yet. (We’re still waiting for Billy to shove a Mexican peso up Sheldon’s nose.)
ONCE AN 'H-O TRAINIAC,' ALWAYS AN 'H-O TRAINIAC'
The boy genius was always loco for locomotives. In fact, the prequel’s first episode opened on a close-up of Sheldon’s model train set. (“I’ve always loved trains,” Adult Sheldon said. “In fact, if my career in theoretical physics hadn’t worked out, my backup plan was to become a professional ticket taker. Or a hobo.”)
SHELDON'S PERFECT PITCH
Sheldon loves to tell people that he has perfect pitch, which he discovered on Day 1 at Medford High. When it was suggested in the pilot by music instructor Ms. Fenley — played by Melissa Tang, who previously guested on Big Bang as Mandy Chow — that he pursue music professionally, the 9-year-old answered, “No thank you. Musicians take drugs.”
In the series premiere, we caught a glimpse of Bob Newhart’s alter ego demonstrating how to power a clock using only a potato — sound familiar? And a signed photo of Arthur Jeffries hangs on Young Sheldon’s bedroom wall. Come Season 4, Episode 11, Sheldon tries (and fails) to make friends at East Texas Tech by starting his very own club in honor of the children’s television personality.
Those who aren’t familiar with Young Sheldon might not know that Dr. Cooper’s childhood friend, whose adult counterpart made an appearance during Big Bang‘s 12th and final season, was first seen on the prequel, not the other way around. On Big Bang, Tam and Sheldon lost contact after attending different colleges. His formal introduction came in Young Sheldon Season 1, Episode 2.
Following five appearances on The Big Bang Theory as nurse Althea Davis, Vernee Watson guest-starred on two episodes of Young Sheldon as Nurse Robinson. The Fresh Prince of Bel-Air vet also played a nurse on Two and a Half Men, and co-stars as Gloria, yet another nurse, on Bob Hearts Abishola.
Suffice it to say, Watson is the glue that holds the Chuck Lorre Cinematic Universe together.
ALWAYS A PASSENGER, NEVER A DRIVER
In Season 1, Episode 3, Young Sheldon declared that seeing 14-year-old Georgie behind the wheel of Meemaw’s car was enough to convince him that he never wanted to operate a motor vehicle — hence his reluctance when Leonard & Co. tried to give him virtual driving lessons in Big Bang Season 2.
SHELDON'S LOVE OF COMIC BOOKS
Tam is singlehandedly responsible for inspiring Dr. Cooper’s weekly visits to Stuart’s comic book store. Sheldon’s childhood friend first introduced him to comics in Season 1, Episode 4.
Long before Adult Sheldon explained to Penny why he had a designated couch cushion, Young Sheldon asked Tam to forfeit his seat in the Medford High cafeteria. “It’s complicated, just move,” he
askeddemanded in Season 1, Episode 4.
WHY SHELDON BECAME A THEORETICAL PHYSICIST
In Season 1, Episode 6, Dr. Cooper informed us that the reason he chose a career in theoretical physics had nothing to do with his desire to unravel the inner workings of the universe. He just wanted to prove he was right to a condescending NASA employee who talked down to him during his freshman year of high school.
After sharing a piece of pumpkin pie with Howard in Season 9 of Big Bang, Musk cameoed in Season 1, Episode 6 of Young Sheldon. The scene in question revealed that Musk found the answer for successfully landing a Space X rocket in Dr. Cooper’s childhood notebook. (Perhaps he can also find something in there about not running Twitter into the ground?)
Long before Sheldon had Penny apply Schrödinger’s Cat to her dilemma about whether or not to go out with Leonard, Young Sheldon detailed the thought experiment to Dad and Georgie on a road trip in Season 1, Episode 8.
SHELDON'S BATHROOM SCHEDULE
Leonard isn’t the only one who’s had to put up with Sheldon’s timetable for bowel movements. It was referenced by Mary in Season 1, Episode 8, and was also a point of contention in Season 3, Episode 16 (see above).
Two years later, in Season 5, Episode 16, Sheldon’s bathroom schedule was shown in full for the first time.
SHELDON'S STAR TREK FANDOM
Our first glimpse at Sheldon’s fandom came three decades before he’d appear in a documentary honoring the late Leonard Nimoy. In Season 1, Episode 9, Shelly explained to Meemaw that “Spock is half-human and half-Vulcan [and] ashamed of his human side… That’s why I identify with him.” Little did he know that he’d one day be gifted a Cheesecake Factory napkin containing Nimoy’s DNA.
Long before Penny reluctantly sang Sheldon’s favorite childhood lullaby while applying vapor rub counterclockwise, Mary sang that soothing song to her germaphobic son in Season 1, Episode 13.
THE FIRST RELATIONSHIP AGREEMENT
Long before Amy crossed any T’s or dotted any I’s, 10-year-old Sheldon drafted his very first social contract: the Cooper-Sturgis-Tucker Behavior Agreement, which clarified his own involvement in Meemaw’s relationship with his mentor, Dr. John Sturgis. But wait, there’s more…
FUTURE REVEAL NO. 1
As Meemaw and Dr. Sturgis signed and dated the aforementioned document in Season 1, Episode 22, our narrator revealed some rather gigantic #Shamy news: “I would go on to draw up such contracts throughout my life, with roommates, with my wife… even with my own children,” he said, confirming that he and Amy would go on to have kids (plural!) after the events of The Big Bang Theory.
Four years later, in the Season 5, Episode 16, Sheldon mentioned that Amy eventually stripped him of his comic book allowance so they could start a college fund for their children.
DR. TIRE: AN ORIGIN STORY
Jerry O’Connell was introduced as Georgie’s adult counterpart during Season 11 of Big Bang, at which point it was revealed that Sheldon’s older brother owned a successful chain of tire stores. A few months later, in Season 2, Episode 8 of Young Sheldon, Georgie took a part-time job at Herschel Sparks’ auto body shop and discovered an affinity for tires. The rest is history.
“If it’s funny, it’s a Bazinga!” That was the slogan for a novelty company introduced in Season 2, Episode 10, which at long last revealed how Sheldon came up with his signature catchphrase.
BLOSSOM? NEVER HEARD OF HER!
Mayim Bialik’s star-making role was referenced in Season 2, Episode 11, when Sheldon’s twin sister Missy pitched a number of potential boyfriends for her Cabbage Patch doll.
MISSY: “How do you think Celeste would look next to Joey Lawrence?”
SHELDON: “I don’t know who that is.”
MISSY: “He’s Blossom’s brother.”
SHELDON: “I don’t know who that is.”
MISSY: “It’s a show. She wears hats.”
Little did Young Sheldon know that his sister was referencing his future wife. (Funnily enough, Big Bang also name-dropped Bialik three years before she was cast as Amy.)
A PRECURSOR TO 'THE GORILLA EXPERIMENT'
Years before Sheldon forced Penny to ponder the question “What is physics?” and documented his findings, the pint-sized brainiac posed an experiment not unlike Project Gorilla and used Missy as a test subject — also in Season 2, Episode 11.
HE'S NOT CRAZY! HIS MOTHER HAD HIM TESTED!
“Bazinga!” might be the catchphrase most commonly associated with Parsons’ alter ago, but “I’m not crazy! My mother had me tested!” is a close second. Sheldon first alluded to said assessment in Season 2, Episode 14, when Georgie asked Sheldon if he was crazy after confronting a bully.
THE NOBEL PRIZE
Season 2, Episode 22 tied directly into the mothership’s series finale. Immediately after Big Bang‘s Sheldon accepted the Nobel Prize in physics, Young Sheldon circled back 28 years to find Sheldon invite the entire school to a party for the 1991 Nobel Prize announcements. Unfortunately, no one showed.
“In that moment, I felt like a neutrino, destined to be alone forever,” Adult Sheldon narrated. “Thankfully, I was wrong,” he said, as younger versions of his future friends were shown, one by one, with Easter eggs aplenty….
The asthmatic Leonard was seen in his signature red robe with an inhaler on his desk.
Wyatt’s “little slugger” had a baseball bat near her bedside. On her wall was a cowboy hat to represent Nebraska, as well as a poster of Los Angeles, suggesting that she already had dreams of becoming an actress.
Howard was in his bedroom, donning his signature silk jammies. To his right was a table of magic tricks and props. Mrs. Wolowitz also made a voice-only cameo, telling her son to “put away the fakakta game” and get to bed.
Howard’s future wife had a microscope on her nightstand to represent her interest in microbiology. A trophy and sash represented her days as a child beauty-pageant contestant.
Raj was still in India. A stuffed tiger on his bed represented the Royal Bengal Tigers. The telescope to his right foreshadowed his future career as an astrophysicist.
Sheldon’s future wife, seen in her signature nightgown, was up late reading her beloved Little House on the Prairie. (Watch the scene and read our post mortem.)
SHELDON'S LORD OF THE RINGS FANDOM
Years before a Lord of the Rings film prop threatened to tear him and his friends apart on Big Bang, Young Sheldon in Season 3, Episode 4 dove into the writings of J. R. R. Tolkien and had dreams where he, too, had transformed into Gollum.
BIG BANG CAMEO NO. 1: KALEY CUOCO
TVLine was the first to confirm that Cuoco made an uncredited, voice-only cameo in Season 3, Episode 10, in which Sheldon had a nightmare where he was taunted by a bacteria-infested pool. She was the first of Jim Parsons’ former castmates to cross-over to Young Sheldon. (Watch the scene and read our post mortem.)
HOT BEVERAGE OF COMFORT (AND FUTURE REVEAL)
It was during the events of Season 3, Episode 12 that the “hot beverage of comfort” became Sheldon’s “go-to method of dealing with someone in emotional distress — and it always worked,” he said. Well, “except when my wife was in labor, where it was suggested that I throw it in my own face.”
When George stumbled upon Sheldon making tea for fellow pint-sized genius Paige, he told his son that he was proud of him. That was all the reason Sheldon needed to continue with this method for years to come.
'A REAL EYE-TALIAN TREAT'
Sheldon first revealed his favorite childhood meal — spaghetti with cut-up hot dogs — to Penny during Season 3 of Big Bang. On Young Sheldon, the pasta dish is Sheldon’s designated Thursday-night dinner. We saw him attempt to make it for himself in Season 3, Episode 21, before Mary served it to the entire family in Season 5, Episode 4.
Long before Sheldon befriended the renowned theoretical physicist, he would score an all-expense paid trip to Pasadena, Calif., where he and George attended an (off-screen) lecture by his scientific hero….
CALIFORNIA INSTITUTE OF TECHNOLOGY
That same episode — Season 3, Episode 16 — found Sheldon and his dad at his future alma mater Caltech. In the tag scene, father and son stood in the doorway of the cafeteria, where Sheldon would one day convene with his good friends Leonard, Howard and Raj. (Watch the prophetic scene and read our post mortem.)
MARY'S NASTY HABIT
In Big Bang‘s Season 2 premiere, a drugged-up Sheldon let slip to Leonard that Mary used to smoke in the family car. Her nasty habit carried over to the prequel, first when Sheldon’s mom was caught smoking in Season 3, Episode 21.
FUN WITH FLAGS
In the Season 3 finale, Sheldon made a videotape to convince Mary to let him go to college. Behind him was a chalkboard, the writing on which mirrored the writing on the whiteboards used as a backdrop for Sheldon and Amy’s long-running web series.
BIG BANG CAMEO NO. 2: MAYIM BIALIK
In the Season 4 premiere, Jim Parsons was reunited with Mayim Bialik, who reprised her role as Sheldon’s wife, Dr. Amy Farrah Fowler, in a voiceover….
In that same scene, as the Coopers gathered in the backyard to commemorate Sheldon and Missy’s respective graduations, Sheldon the Narrator (voiced by Parsons) said that “it was the best graduation party I had been to… until we had one for my son, Leonard Cooper.
“I wanted his name to be Leonard Nimoy Cooper, but Amy wouldn’t let me,” he revealed. That’s when Bialik chimed in as Sheldon’s better half and said, “Be lucky I let you name him Leonard.” (Read our post mortem.)
Sheldon’s mortal enemy was first referenced in Season 4, Episode 11, when TV’s erstwhile Wesley Crusher caught Missy’s eye.
MISSY: “Wil Wheaton’s cute.”
SHELDON: “If you like him, you should watch Star Trek with me.”
MISSY: “He’s not that cute.”
In Season 4, Episode 13, a new tradition was born when Sheldon proposed a science-based car game to his mother: “I’ll say an element starting with the letter A, then you repeat that and add one starting with the letter B.” As our narrator would explain, this tradition “would eventually bring countless hours of joy to Leonard on our drives to work. Much like my mother, he never beat me.”
SHOW ME THAT SMILE AGAIN
Dr. Cooper first struggled to flash a grin in when Raj was profiled for People magazine. In Season 5, Episode 4 of the prequel, Sheldon found it difficult to convince George that he was happy having his own bedroom, separate from twin sister Missy.
WHY SHELDON SAYS 'COITUS'
During Season 5, Episode 6, Adult Sheldon revealed why he’s always used an alternative word for sex. “Every culture has their taboos,” he said. “In the Ukraine, it’s rude to whistle in doors — and they’re correct. Not a fan,” he pointed out, reinforcing his no-whistling policy first cited in BBT Season 2.
“In our society, any discussion of human reproduction seems to be so upsetting that it causes chaos,” he continued. “Even the word ‘sex’ provokes an uncomfortable reaction. I thought ‘fornicate’ might work, but that seemed too judgy.”
It’s at that point that the 11-year-old reached for his thesaurus and landed on the perfect word — “a word so bland and clinical that it would be impossible to take offense to it.”
BIG BANG CAMEO NO. 3: SIMON HELBERG
Helberg reprised his role as Howard Wolowitz in a voiceover capacity during Season 5, Episode 7 — “An Introduction to Engineering and a Glob of Hair Gel” — which told the origin story of Sheldon’s “complicated relationship with engineering.” (Watch a clip here.)
After Teller played Dr. Cooper’s father-in-law Larry in Seasons 11 and 12 of Big Bang, Penn and Teller popped up in Young Sheldon‘s Season 5 finale as dermatological duo Acne and Pus.
SHELDON'S FIRST GRAPHIC TEE
On the precipice of adulthood, Sheldon in the Season 5 finale swapped his signature button-down shirt for his very first graphic tee: a red crewneck with a Flash emblem, not unlike the one he frequently wore on Big Bang. (Read our post mortem.)
ACOUSTIC SWEET SPOT
In the Season 6 premiere, the Coopers arrived for Sunday service and took a seat in the back of the church — much to Sheldon’s chagrin. When Missy asked her brother what was wrong, he answered, “We’re nowhere near the acoustic sweet spot,” which was first referenced in Big Bang Season 2. (Read our post mortem.)
GEORGIE'S FIRST WIFE...?
Young Sheldon in Season 1 said that Georgie will be married at 19. Meanwhile, Big Bang‘s series finale inferred that Sheldon’s older brother marries and divorces twice by 2019. That means new fiancée Mandy could be his first wife.
DR. TIRE: A FAMILY BUSINESS...?
In Season 6, Episode 7, Young Sheldon viewers were introduced to Georgie’s prospective in-laws, who run a tire shop of their own. Could McCallister Auto and Tire eventually be converted into the first Dr. Tire location?
SHELDON'S STINT IN GERMANY
In the Season 6 finale, 13-year-old Sheldon and his mother Mary headed to Germany so that Sheldon could participate in a summer research program at the University of Heidelberg. Big Bang alluded to this trip in Season 1, when Sheldon told Penny that Mary accompanied him while he was a visiting professor at the Heidelberg Institute — only then, Sheldon said he was 15, not 13.
So, why rewrite history? Well, Sheldon’s recollection of his stint in Germany predated Sheldon telling Bernadette’s father that George died when he was 14 — a piece of dialogue that came in Big Bang Season 7 and is now considered canon.
When Sheldon told Penny about his trip to Germany on Big Bang, he said that his mother flew back to Texas to help his dad after their house slipped off cinderblocks. “It was tornado season, and it was an aluminum house,” he explained. But clearly Sheldon’s memory was a bit fuzzy, because it wasn’t his childhood home that suffered the brunt of the damage. It was Meemaw’s house, which was destroyed in the storm. And that’s where we left things as the prequel closed out Season 6.