The identity of the next star of Doctor Who will finally be revealed - and it could be a woman, the BBC have confirmed.
After weeks of speculation, the 11th Doctor will be revealed in a special edition of Doctor Who Confidential, to be aired on BBC One on Saturday at 5.35pm.
David Tennant announced in October he would be stepping down from his role as the Doctor at the end of this year.
The next Doctor will take over in the series that will air in 2010.
With a new creative team in place for the latest series led by executive producers Steven Moffat and Piers Wenger, the casting of the Doctor was the first job to be completed before scripts could be finalised and shooting could begin in summer 2009.
In a statement, implying the new Doctor could be a woman or a man, the actor playing the role will be giving "his or her initial reaction to being the new, 11th incarnation of one of television's most loved characters," the BBC said.
The Doctor Who Confidential programme will also be broadcast live on BBC Big Screens nationwide.
Head Of Drama BBC Wales Piers Wenger said: "We are so pleased to have been able to cast this person as the new Doctor. We believe the actor is going to bring something very special to the role and will make it absolutely their own - I just can't wait to tell everyone who it is - it has been a nail-biting Christmas trying to keep this under wraps!"
There will be four Doctor Who specials featuring Tennant that will run in 2009 into New Year 2010.
The identity of David Tennant's replacement as Doctor Who will be revealed in a BBC1 show to be broadcast tomorrow – and simulcast live on the BBC's big outdoor screens in cities around the country.
It is understood that those hoping for the first female doctor will be disappointed. Doctor Who's new executive producers, Coupling creator Steven Moffat and BBC Wales head of drama Piers Wenger are said to have stuck with tradition and cast a man in the role.
However, Moffat and Wenger are thought to have steered away from the more obvious names that have been linked to the role.
Tennant's replacement will be unveiled in an edition of Doctor Who Confidential to be broadcast on BBC1 at 5.35pm on Saturday, 3 January, featuring an interview with the actor who is to be the 11th doctor in the long-running BBC1 sci fi drama, successfully revived by the corporation in 2005.
The show will also be broadcast live on BBC outdoor screens around the country in city centre locations including Hull, Liverpool, Rotherham, Swindon, Swansea, Norwich and Walthamstow.
Tomorrow's announcement will put to an end months of speculation over who will take over from Tennant, who confirmed live on air during ITV1's National Television Awards at the end of October that he will step down from the starring role in Doctor Who after a series of specials to be broadcast next year.
In recent weeks prominent actors including James Nesbitt, David Walliams and David Morrissey, who starred alongside Tennant in the Christmas Day Doctor Who special, have been linked with the role by bookmakers.
Less obvious names mentioned as potential replacements for Tennant have included Paterson Joseph, perhaps best known as Johnson in Peep Show, and more recently seen in BBC1's Survivors; Dirty Pretty Things actor Chiwetel Ejiofor; Ben Wishaw, whose credits include Criminal Justice; and Russell Tovey, who was in last year's Doctor Who Christmas special and also appeared in recent BBC1 Dickens adaptation Little Dorrit.
"We believe the actor is going to bring something very special to the role and will make it absolutely their own. It has been a nail-biting Christmas trying to keep this under wraps," Wenger said.
The BBC added that choosing the next Doctor Who now was "job number one" so that scripts could be finalised and shooting could begin in the summer on series five of the show for broadcast in 2010, even though Tennant will not bow out until the Christmas 2009 special.
Doctor Who fans will discover the identity of the latest actor to play the Time Lord.
Paterson Joseph is the runaway favourite and would become the first black man in the role.
David Tennant announced in October that he was stepping down after filming four special episodes in 2009. Since then fans have been busy debating on internet forums who will take over.
David Morrissey, who starred in the Doctor Who Christmas special, was previously a favourite.
There has also been speculation that Billie Piper, who played the Doctor's assistant Rose Tyler, would become the first woman to take the part.
Tennant's replacement, the eleventh Doctor since the programme was first aired in 1963, will be revealed in Doctor Who Confidential on BBC One at 5.35pm.
The BBC have kept the actor's identity a close secret but did admit they made the decision over Christmas. He or she will star in the 2010 series, due to begin filming in the summer.
Joseph, 44, was the leading contender, with bookmakers William Hill last night putting him at 4/6.
He has starred in two previous Doctor Who episodes, both in 2005, and once commented 'any actor would love the challenge' of playing the character.