The Battlestar Galactica spin-off Caprica has announced their lead actress, according to io9:

Paula Malcomson, best known for her work as Trixie in Deadwood, will help bring the soap operatics to the “Dynasty in space” backdoor pilot.

Malcomson is playing a double agent, who is having an affair with her husband’s rival, and passes on secrets that help create the first Cylon.