Tricia Helfer

Tricia Helfer plays Number Six in Battlestar Galactica. The appearance is immediately recognisable, but the performance does more than provide a striking image. Her calm delivery makes James Callis's Gaius Baltar seem even less able to manage himself, and she gives their exchanges an odd, often very dry humour.

Helfer came to acting after a modelling career. Her television roles include Viondra Denninger in Ascension, as well as work in Lucifer and Burn Notice. She also voices Sarah Kerrigan in StarCraft II.

Number Six remains the clearest demonstration of how effectively she can use stillness. She doesn't need to compete with Callis's nervous energy. Letting him do the worrying can be enough to take command of a scene. That contrast gives their partnership far more life than the familiar image of the red dress suggests.