“Kneeling is a stunt for me,” 47-year-old Nathan Fillion told TV critics at TCA of the rigors of starring in ABC’s new cop drama The Rookie.

Written by former Castle executive producer/co-showrunner Alexi Hawley, The Rookie stars Fillion as John Nolan, a guy who leaved his comfy small-town life after a divorce and moves to LA where he becomes the oldest rookie in the LAPD. Playing a guy who has trouble scaling a fence, and gets winded chasing bad guys, was no stretch, physically, Fillion joked.

“If I can have a stunt guy run down the street for me, and these knees” so much the better, he explained.

“You make your way through your career playing somebody’s son, ad then somebody’s brother, and then suddenly you’re married and have a baby, and the baby is 14, and 22 and now you’re the oldest,” Fillion said of an actor’s trajectory.

“That’s your title. You’re The Oldest. That happens. I feel fortunate” he said of his latest series project. “I still feel a little bit relevant.

“This is the new normal” in our culture, Fillion said, remembering marriage was once The Norm, then divorce became The Norm. “Now it’s the reboot, the do-over. Not everybody is going to become a rookie cop” he conceded, but he guessed everyone in the the room has either had this experience or knows someone who has.”

Alexi Hawley described Fillion’s John Nolan character, who is based on an actual LAPD cop, as someone who is a rookie in his 40’s – twice the age of his fellow rookies. Meanwhile, other character who are his age are his superior.

“He lives in this in-between place,” Hawley described.

Asked if he’s worried the audience for this series is AARP aged, Hawley responded: “I think with the explosion of television in the last 10 years – [FX Network/FX Productions CEO] John Landgraf always comes up here and tells you how many shows are on the air, and it’s a lot” – this show is accessible to a wide range of viewers.”

They’re not targeting anyone other than “anybody who wants to watch,” he insisted.

The series came about when Mark Gordon called Hawley, saying he had the life rights to a guy who moved to Los Angeles and became the oldest rookie on the LAPD. “I immediately understood the potential of that character,” Hawley said.

That quickly turned into a conversation about whether Fillion would want the starring role so soon after his years on Castle.

“He really responded to the character, Hawley told TV critics.

“I couldn’t say no,” Fillion chimed in. “This January I will have been 25 years in the business. I see an opportunity; I know what to do.”