James Marsters will be guest-starring in an episode of the R-rated Doctor Who spin-off, Torchwood.

Perhaps best known as Spike in the Buffy the Vampire Slayer and Angel teevee series and as well as Dr. Milton Fine in Smallville, Marsters has also voiced the role of Lex Luthor in the upcoming D2DVD Superman: Doomsday. He is also a musician and singer, playing solo and as lead singer of Ghost of the Robot.

The second season of Torchwood goes up in the U.K. after the first of the year; the first season goes up on BBC America in September.