Chicago Fire: NYPD Blue's Kim Delaney Cast as Kelly Severide's Mother

Chicago Fire Kim Delaney

Chicago Fire is finally completing Kelly Severide’s troubled family tree, tapping NYPD Blue alumna Kim Delaney to play the firefighter’s mother, TVLine has learned.

Delaney will guest-star in an upcoming Season 6 episode as Jennifer Sheridan, who is described as warm, scripture-quoting and church-going. Severide’s mom may have at one point partied like it was 1979, but she has now embraced the straight and narrow path. While she may claim to have moved on from the past and her messy divorce from ex-husband Benny (played by Treat Williams), old habits die very hard.

As viewers might recall, Severide was raised by his mother after his dad left the family, but the young man didn’t have an easy home life. During high school, Severide lived with Chicago Med‘s April Sexton and her parents for a period of time.

“We’ll have an explanation for why you haven’t seen [Jennifer] in five years that won’t be crazy,” executive producer Derek Haas previously told TVLine. When she comes back, “it’s not a shocker, it’s not a surprise, to Severide.” Haas also expressed her desire to get Williams back for the storyline, “but it’s hard because he’s not a regular on our show,” the EP noted.

In addition to her role as Det. Diane Russell on NYPD Blue, Delaney’s many TV credits include Army Wives, The O.C., CSI: Miami and Philly.

Chicago Fire returns with new episodes after the Olympics, on Thursday, March 1 at 10/9c on NBC.