According to reports, the 46-year-old actor, who played Spike in Joss Whedon's Buffy, will feature in at least three episodes in the role of Barnabus Greeley, a dangerous terrorist leader.
He will be joined in the Battlestar Galactica prequel by the previously announced Patton Oswalt, Sasha Roiz, Eric Stoltz, Esai Morales, Paula Malcomson and Polly Walker.
Marsters has also appeared in Torchwood, Angel and Smallville.
Caprica is slated to begin airing on Syfy Friday, January 22, 2010.
