Jane Tranter, the corporation's controller of drama, said that Billie Piper will feature in every episode of series two and the Christmas special as The Doctor's sidekick Rose Tyler.
News of a third series comes ahead of first series finale when Christopher Eccleston's doctor will take his bow as he is killed off in a battle with the Daleks in a episode called 'The Parting of the Ways'.
Eccleston made the decision to quit the show at the end of March for fear of being typecast. He is being replaced by 'Casanova' star David Tennant, who will take over as the 10th time lord.
The death of Eccleston's doctor will also mark a fresh turn for 'Doctor Who' because it will feature the first ever screen kiss between a doctor and his assistant when The Doctor kisses Rose.
That will not be the only kiss on screen. There will also be a quick smooch between The Doctor and his other assistant Captain Jack Harkness, played by John Barrowman, whose sexuality has been left open to question since he joined the show.
The last episode of the current series will also reveal the identity of 'Bad Wolf', which has featured as a head message throughout the series.
Speculation as to who 'Bad Wolf' is has created an online frenzy with fans wondering if the cryptic message that has appeared throughout the series could relate to an old foe such as one-time Dalek leader Davros.
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