Arrowverse Crossover: Scoop On 'Crisis On Earth-X'

The Flash actress Candice Patton did more than just wear Iris' fairy tale wedding gown; she picked it out! "They actually flew me to L.A. to go to Monique Lhuillier to find a dress for Iris," Patton says. "There's a line in the script about how Monique Lhuillier dresses are indestructible. She really goes through it in this episode in this wedding dress, and it's still pristine... The first dress I tried on, we were like, 'OK, this is it. This is great. Feels good. Comfortable.' The most important thing was, 'Am I comfortable? Am I going to be able to, like, run away from aliens or whatever?'"

"We've been leading up to this wedding for a long time," The Flash star Grant Gustin says. However, Barry and Iris' big church ceremony doesn't take place on the show that regularly features the couple, but on Supergirl. "We've consistently had these crossovers, and we're bringing so many characters together for this wedding, it's kind of fitting that it happens somewhere else," the actor explains.

Broadway vet Jesse L. Martin's Joe "doesn't sing at the wedding. But there is music at the wedding," Valdes hints. Hmmm...

Get your tissues ready, because Joe gives "a beautiful speech" during the rehearsal dinner, shares Carlos Valdes, who plays Barry's best man Cisco. "That's the thing about Jesse [L. Martin] that kills me: No matter how ambiguous it looks on the page, he gets up there, and he just gives it heart and commits to it, whatever the line is, whatever the action is, and everybody just melts. That's his superpower."

For the Danvers sisters, the wedding day crisis "is very much a duke-it-out [situation], like, 'We're here together. We're in this,'" Leigh describes. "At certain moments, we're fighting for each other, fighting to get to each other, and fighting together. You really get to see a lot of sides of everybody, and sides that you wouldn't expect."

And for Supergirl leading lady Melissa Benoist, having her co-star in the mix was a welcome treat. "I always wished that she had been by my side for every crossover that I've done," Benoist says. "Because they are always so massive and such undertakings, workload-wise. I said to myself at the end of last year's crossover, 'There's no way it could get bigger than this. How are they going to write something bigger than this?' Well, they wrote something massive that was overwhelming to read — in an exciting way, of course."

As per usual, Mick is "just taking the piss out of everyone, it seems, on the four shows," Legends star Dominic Purcell shares with a laugh. "He's just having a blast, having a lot of fun." And there's one particular character with whom Heat Wave would like to have fun: "Rory has the hots for Killer Frost," Purcell previews. "He's had a crush on her for quite some time. Whether or not that will develop into anything, I doubt it, because I'm not sure if Rory can be tamed at this point."

Arrow's "Mr. Terrific definitely has a bigger footprint in this crossover than last year," Echo Kellum previews. "I think he really helps figure out some stuff [about] what's going on with Crisis-X." Curtis also has "a little chemistry" with Earth-X's gay superhero The Ray (played by Quantico and Looking vet Russell Tovey). "We had some fun scenes that we shot together," Kellum teases.

Speaking of doppelgängers, Amell also portrays Dark Arrow, while Oliver must deal with Earth-X's version of Prometheus. The "payoff" with that latter plot "was really worth it" and leads to "one my favorite scenes of the entire season," Amell raves.

This year's crossover required Benoist to also play Supergirl's evil Earth-X doppelgänger, Overgirl. "I did wear a very different outfit," Benoist describes. "There's still a cape, and my face is covered, and she's not so nice. It was pretty challenging. I've had moments like that on [Supergirl] with Bizarro and when Martian Manhunter takes over Kara's body, but this was entirely different. This was not even red Kryptonite-esque. This was way worse."

"The best thing that we got to do was the big gathering of everyone here in our world, on the Waverider, which was pretty awesome," Legends star Brandon Routh says. "It was a really unique and fun thing." But pulling off the epic scene was not an easy feat. "We used to get upset about [having] nine characters on the bridge and figuring out how to shoot that, but having 21 or whatever it was is pretty insane," the actor notes. "But Greg Smith, who was our director for our episode, knew what he wanted pretty quick. You have to have your ducks in a row when doing a crossover because people are coming from four different shows, like, 'We have Melissa [Benoist] for two hours, and we have Grant [Gustin] for an hour, and we have Stephen [Amell] for 30 seconds!' So gotta get the shot!"

In addition to more interaction with Legends like Sara Lance and Mick Rory, as well as sharing screentime with the Danvers sisters, Iris has "a lot, a lot, a lot" of scenes with Arrow's Felicity. "We kind of team up in the crossovers," Patton teases.

Unlike last year's crossover, during which Alex was MIA, this time around, "I'm all over it!" Supergirl's Chyler Leigh exclaims. "Every day, 14-hour camera days, every single day for three and a half weeks."

Alex and Kara are the sole Earth-38 citizens to travel to Earth-One for Barry and Iris' nuptials, where "disaster ensues" when the Earth-X baddies invade. "It's everybody banding together and figuring out strengths, weaknesses," Leigh describes. "You have all these minds in one place, and all these superpowers in one place, all these costumes in one place. I was like, 'I'm really glad that I have a DEO outfit. Like, I'm super stoked about this.'"

Now that The Flash's Caitlin has a costumed, superpowered alter ego, "I finally got the chance to sort of suit up, as it were, and get out there and fight with everyone," Danielle Panabaker says. Plus, the actress shares "some really funny interactions with Dom [Purcell]. Heat Wave's really into Killer Frost. He'd really like to know a little more about her. He'd really like to figure out how to make [Killer Frost] come out, as well!"

As far as memorable character interactions in the crossover go, Arrow star Stephen Amell says he "really enjoyed Oliver and Kara's stuff — but not in the way that you might think." Adds his co-star David Ramsey: "Stephen [Amell] and Melissa [Benoist] particularly shine. They really do a fantastic job."

Not to be outdone by the Kara and Oliver scenes, the Scarlet Speedster and the Girl of Steel also have some "fun, classic Barry-and-Kara interactions," Gustin says. Plus, Barry meets "a couple new characters."