Dr Who star Billie Piper is to leave the series - in a nail-biting episode set to have fans gripped.
Billie, 23, who plays sidekick Rose Tyler will leave at the end of this series in a programme called Doomsday.
Rose and the Doctor are battling against a huge invasion set to destroy the Earth, but top writer Russell T Davies won't say if Rose lives or dies.
Billie said: "Rose and I have gone on the most incredible journey over the past two years."
She added: "It has been an amazing adventure, and I can confirm it comes to an end - for now at least - as series two climaxes."
Rose has been companion to both the ninth and tenth doctors and has landed on space stations where she's been a contestant in a deadly version of The Weakest Link; travelled back in time and met Queen Victoria, Charles Dickens, Madame du Pompadour and her dead father.
She has also battled against the Doctor's deadliest foes the Daleks and Cybermen; taken on Slitheen, Sycorax and Krillitanes and survived the end of the world and the blitz.
Russell T Davies said he would miss working with Billie and she would be leaving the programme with "a stunning exit".
He said: "I can't guarantee who will survive and who won't, but I can assure you the Tardis is going on its scariest journey yet."
The role earned Billie the most popular actress title at last year's National Television Awards.