The Doctor From Gallifrey 

The first casting news for the 2012 Christmas Special has been revealed. The BBC announced at Midnight that Richard E. Grant would appear, having previously teased him as an "iconic star". We thought that is probably the wrong choice of words and you might recognise him only as that guy from that thing. Grant has starred in over 80 film and television hits including Withnail And I, The Scarlet Pimpernel, Jack & Sarah, Gosford Park and The Iron Lady. But he's probably best known to Doctor Who fans for playing the Doctor, twice. Briefly during "The Curse of the Fatal Death", a comic relief spoof but for longer in an animated series called "Scream of Shalka". Grant said he is "honoured" to be joining the show.

Also appearing is Tom Ward, who you might recognise as Silent Witness's Harry Cunnigham. The special see Matt Smith's Doctor meet his new companion, played by Jenna Louise-Coleman. 

[Source: BBC Doctor Who]