One of Cox's earliest roles was the Childlike Empress in the 1994 film The NeverEnding Story III.
[2][3] Cox played the character Sophie Aronnax in 20,000 Leagues Under the Sea in 1997,[4] and in 1999 she appeared as Giulietta in the film adaptation of Alegría.
[5] Cox portrayed Princess Irulan in the 2000 Sci Fi Channel miniseries Frank Herbert's Dune and its 2003 sequel, Frank Herbert's Children of Dune.
[6][7][8][9] Cox starred with Jean-Claude Van Damme in Second in Command (2006),[10] and in 2007 was the female lead in The Riddle.
[12] Cox portrayed a fictionalised Mary Shelley, a companion of the Eighth Doctor, in the Big Finish Productions Doctor Who audio dramas The Company of Friends (2009),[13] The Silver Turk (2011),[14] The Witch from the Well (2011),[15] and Army of Death (2011).