Doctor Who's real identity will be revealed next month.
The show celebrates its 50th anniversary later this year and May 18th's episode, 'The Name of The Doctor', will be the start of the commemoration of the landmark date.
Showrunner Steven Moffat told The Sun newspaper: "The 50th starts here. The Doctor's secret is out - and everything's going to change."
Meanwhile, it has been claimed show bosses will use hi-tech wizardry to allow current Time Lord Matt Smith to mingle with former Doctors - including the late William Hartnell and Jon Pertwee - in the anniversary episode.
Matt's alter ego will be placed into clips from previous decades to make it look as if he is part of the scene and interacting with previous incantations, played by actors including Peter Davison, Colin Baker and Tom Baker.
According to the Daily Star newspaper, Matt's predecessor David Tennant is the only actor who will appear in the episode in the flesh.
David recently admitted it was "strange" returning to the show, but he was enjoying filming.
He said: "It is strange being back in the same suit, but it also feels very familiar and comfortable.
"There's nothing quite like 'Doctor Who'. It has a wonderful excitement about it. I always had happy times there."
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