Karolina I. Wydra (born March 5, 1981) is a Polish-American actress and model. She is best known for playing Dominika Petrova on the Fox medical drama series House, and the vampire Violet Muzurski on HBO's dark fantasy series True Blood. Wydra has starred in the fantasy thriller After (2012), and the science fiction film Europa Report (2013). She then portrayed Detective Dianne Kubek on ABC's short-lived crime drama series Wicked City.