Got a story? Text: 63000 - Email: talkback@the-sun.co.ukThe telly beauty, who plays Rose Tyler, will bow out of the BBC1 time-travelling hit during a battle with the Cybermen.
Bosses have already picked her replacement, who will join star David Tennant filming the third series in five weeks time.
Last night Billie said: “Rose and I have gone on the most incredible journey over the past two years, and I can confirm it comes to an end, for now at least.”
She was expected to return for a few episodes of the third series. But Rose will die in an episode aptly named Doomsday, featuring a huge invasion set to destroy Earth.
Show writer Russell T Davies said: “Its been a wonderful experience working with Billie. Well miss her.”
Billie won Most Popular Actress at The National Television Awards last year. She is is currently filming the BBCs adaptation of Philip Pullmans book The Ruby In The Smoke, playing heroine Sally Lockhart.