Think "Moonlighting" meets "Murder She Wrote" when ABC premieres its new romance-mystery series, "Castle."
At least that is what Nathan Fillion, who stars as Richard Castle, tells ET. Castle is a murder mystery writer, who kills off the lead character in his successful series, and finds inspiration when a real-world copycat killer starts knocking people off the same way he did in his books.
"I will be your Jessica Fletcher," he jokes, referring to the character played by Angela Lansbury.
It isn't long until Kate Beckett (Stana Katic), a New York City detective, who is also a fan, shows up at his doorstep to interview him. Castle works with her to solve the crime -- and sparks fly -- so does the aforementioned inspiration. Castle decides to base his new murder mystery series on a woman detective and pulls strings -- he has a lot of friends in high places -- so he can shadow Kate as she solves crimes.
"Either she will have to marry him or kill him," jokes Stana.
Nathan, of course, is an alum of another ABC series, "Desperate Housewives," on which he played Katherine's (Dana Delany) husband.
"Lovely, lovely group, really nice people. I made a lot of friends. They were very kind to me. But I spent a lot of time sitting around in a living room saying 'Uh-huh. Yes. That's right. Well, I'll back you up on that.' I decided in my next job, I wanted to ... I'm an actor. I have that wonderful job where every day can be an adventure for me. That's what Castle is. Every day of his life is a field trip. He's a child inside."
Prior to landing the role of Castle, Nathan wasn't much of a mystery novel reader. But since he was cast, he has started reading Clive Cussler, James Patterson and now is deep into Robert Parker's Spenser For Hire series.
"Something that Robert Parker has done very, very well is his attention to detail," Nathan adds. "That's also, I think, one of Castle's strengths. He pays very, very close attention. He is a spoiled brat. He does kind of do his own thing. He's kind of in his own world, but he's a clever guy. He's very, very clever."
And, if you are clever, you will notice in the series' premiere, when Castle plays poker with Patterson and Stephen J. Cannell -- it is the real authors playing themselves!
"Castle" premieres Monday, March 9 at 10 p.m. on ABC.