The name of the actor who will replace David Tennant as Doctor Who is set to be announced in a special programme on Saturday.

Tennant announced in October that he would be standing down from the role after filming four special episodes, the last of which is due to be screened in early 2010.

His replacement will be revealed in a special edition of Doctor Who Confidential, due to be shown at 5.35pm on BBC1.

The casting was confirmed over Christmas, with filming on the series due to begin in the summer.

The BBC confirmed that in Saturday’s show the actor taking over as the Doctor would be giving “his or her initial reaction” to landing the part.

“We believe the actor is going to bring something very special to the role and make it absolutely their own,” said Piers Wenger, head of drama at BBC Wales, which produces the show.

“I just can’t wait to tell everyone – it has been a nail-biting Christmas trying to keep this under wraps!”

Names which have been linked with the role include Cold Feet star James Nesbitt, Life On Mars actor John Simm, and David Morrissey, who appeared in the Christmas special with Tennant.

Another early favourite is actor Paterson Joseph, who appeared in two Doctor Who episodes in 2005 and was more recently seen in the BBC1 show survivors. Bookies have offered odds of 3-1 on him becoming the first black Doctor.

And there is even speculation that a woman might step into the frame, with comedienne Jennifer Saunders, Hollywood star Catherine Zeta Jones and former Doctor Who assistant Billie Piper all linked to the role.

“Whoever becomes the Doctor has got to take on a whole new life,” the show’s outgoing producer Russell T Davies said last month. “It’s not just becoming part of a TV show.”