Rejoice, Buffy the Vampire Slayer fans!

James Marsters has signed on for a sizable role on Caprica.

The actor - who has appeared on Smallville and Saving Grace, but is best known as Spike from the aforementioned Joss Whedon series - will portray a terrorist leader named Barnabus Greeley on Caprica. He'll appear in a minimum of three episodes.

The Battlestar Galactica prequel debuts on SyFy on January 22.

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.