Playing House: Keegan-Michael Key goes behind the scenes of season 3's cancer story line

USA’s Playing House, a whimsical comedy about two best friends living and raising a baby together, was inspired by the real-life friendship between creators Lennon Parham and Jessica St. Clair. And when it came to the third season, the pair again drew from real life — only this time, they wrote in St. Clair’s battle with breast cancer, therefore chronicling their most personal story yet.

The story arc became a standout from the season and has won praise from critics for its often hysterical portrayal of the struggles of dealing with, as St. Clair put it in her own words, cancer and winning her “perfect set of boobs” at the end. Playing House took a closer look at how women support each other through their toughest crises, and it’s been celebrated for its honesty.

Though the focus of the comedy remains on Parham and St. Clair’s duo, Keegan-Michael Key also played a pivotal role as Mark, St. Clair’s character’s love interest who also helps her through the surgery and recovery. As a comedian, working on the women’s personal story meant walking a fine line between delivering the show’s fiction and staying true to what happened to St. Clair between the seasons.

“I wanted to make sure I was representing Jessica’s reality exactly the way she wanted it,” he tells EW of how he approached his scenes with St. Clair. “She’d always write this note [that said], ‘Remember, our show is lady porn,’ and so sometimes she’d say to me, ‘My husband Dan [O’Brien] did X, Y, and Z, and I want you to do exactly what Dan did,’ and other times she’d say, ‘I want you to be the best version of what I wish Dan did.’ I felt very honored to be asked to be a part of the telling of her story. This season took it to another level, and it was nice to be able to stretch and to use muscles I haven’t used in quite some time.”

“It didn’t feel much different from before,” he adds. “They’re both lovely and have a great eye for what they’re doing and they share a brain. They’re both the best part of either side of the brain. Lennon’s so good at showing restraint and staying on story and Jessica’s whimsy encapsulated, so they’re two parts of a brain… It was an honor and a privilege [to be a part of the story line in season 3]. It was such a lovely, lovely thing to do, to be in concert with them.”

Besides, Key recalls, the show has always been personal for him from the start. “The girls were the first people to have ever given me a shot,” he says. “The reason I did Playing House in the beginning was because I had done Jill Soloway’s Afternoon Delight with Jessica, and she was like, ‘Lennon and I want you to come on and we want you to be the romantic lead and we want you to be sexy and we believe you can do that, if that’s something you’re interested in doing.’ And I said, ‘Funny you should ask, that’s exactly the direction I want my career to go in.’ So they have given me a lovely gift.”

Playing House airs its season 3 finale on USA Friday at 11 p.m. ET. The full season is now available On Demand and online.