James Nicholas Callis is an actor. He is known for playing Dr. Gaius Baltar in the show "Battlestar Galactica" and Bridget Jones' best friend Tom in the Bridget Jones film series. He appeared in the television series Eureka and 12 Monkeys on Syfy, and he voiced the character Alucard in the Netflix series "Castlevania" and "Castlevania: Nocturne."