Buffy The Vampire Slayer

HOLLYWOOD (Variety) - Nathan Fillion is joining the cast of "Buffy the Vampire Slayer," taking on a key role in the final five episodes of the about-to-wrap series.

Fillion, who most recently starred in "Buffy" creator Joss Whedon’s short-lived Fox television drama "Firefly," will play Caleb, a former man of God who’s turned to the dark side and now follows a "Buffy" baddie known as the First. Fillion’s first segment airs next month.

"Nathan Fillion has a leading man’s looks, but he’s actually horribly evil, so he makes Caleb the epic foil for Buffy that he needs to be," Whedon said. "Caleb calls himself a preacher, but his habit of murdering girls and his alliance with the darkest evil known to man makes him exactly the sort of guy whose (butt) Buffy needs to kick."

The actor’s feature credits include "Saving Private Ryan" and "Blast from the Past." He also is working on a pilot for NBC.

Whedon last month confirmed that this season will be the final one for "Buffy," which has aired on UPN for the past two seasons and previously spent five years at the WB. The series finale of the cult fave will air in May.