ABC’s hit show CASTLE, wrapping up its third season Mondays at 10 PM and coming back for a fourth season, is named for its hero. Nathan Fillion’s Richard Castle is a hugely successful NY-based mystery novelist who lives with his mother Martha (Susan Sullivan) and teenaged daughter Alexis (Molly Quinn). He has become unofficial partner to NYPD homicide detective Kate Beckett (Stana Katic), who treats Castle with a combination of affection, annoyance and attraction as he trails her, ostensibly as inspiration for his writing, but clearly more because he just enjoys her company.

For anyone who doesn’t know Fillion’s pre-CASTLE background, the actor from Alberta, Canada is perhaps best known and loved for his portrayal of Mal Reynolds, antihero spaceship captain on the short-lived science-fiction Western series FIREFLY and its theatrical sequel SERENITY.

Fillion also been a regular on ONE LIFE TO LIVE, TWO GUYS, A GIRL AND A PIZZA PLACE, DRIVE and DESPERATE HOUSEWIVES, had a notable character on LOST, and starred in Joss Whedon’s hit Internet musical mini-series DR. HORRIBLE’S SING-ALONG BLOG, as well as appearing in the feature films WAITRESS, SLITHER, TRUCKER and SUPER.

ASSIGNMENT X: When ABC approached you about CASTLE, had they been looking for something to do with you after you were on LOST and DESPERATE HOUSEWIVES?

NATHAN FILLION: I sure hope so. You always hope that you’re somewhere in their hearts, don’t you? [Read The Rest Here]