When she was 19 years old she moved to Hollywood where she has since stayed. In 2007 she starred in Species: The Awakening, and has been cast in the film You and I. Mattsson also appeared in the music video of Primal Scream's "Country Girl" in 2006. She appeared in the Touchstone Pictures film Surrogates and also in three episodes of the ABC series Desperate Housewives as Irina. She plays Alexis Blume on the TV series 666 Park Avenue. In the television series Nikita she played Cassandra .