One of Cox's earliest roles was the Childlike Empress in the 1994 film The NeverEnding Story III.
1996
She played Diana, Princess of Wales in Princess in Love by David Greene, a film released in 1996 based upon the publication by Anna Pasternak.
1997
Cox played the character Sophie Aronnax in a remake of 20,000 Leagues under the Sea in 1997, and in 1999 she appeared as Giulietta in the film adaptation of Alegría.
2000
She played Princess Irulan in the Sci Fi Channel's 2000 miniseries Frank Herbert's Dune and its 2003 sequel, Frank Herbert's Children of Dune.
She also played The Childlike Empress in The Neverending Story III.
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.
2006
Cox starred with Jean-Claude Van Damme in Second in Command (2006) and in 2007 was the female lead in The Riddle alongside Vinnie Jones, Derek Jacobi, and Vanessa Redgrave.
2008
She starred in The Oxford Murders with Elijah Wood and John Hurt in 2008.
Cox portrayed a fictionalised Mary Shelley, a companion of the Eighth Doctor, in several Big Finish Productions Doctor Who audio dramas, including The Company of Friends, The Silver Turk, The Witch from the Well and Army of Death.
Cox lives in Bristol, with her partner and has a son named Luke.