Withnail and I star Richard E Grant is to star in the Christmas edition of Doctor Who, the BBC has announced.
The actor previously played the time-travelling Doctor himself in 2003, in the online animated series Scream of the Shalka.
Grant also played an unofficial "Tenth Doctor", aka "The Quite Handsome Doctor", in a 1996 Comic Relief sketch.
The 55-year-old said he was "honoured" to be in the Christmas special, which starts filming this week.
No details have been released of his role in the show, although it is rumoured he will play the villain.
He will be joined by Tom Ward who, until recently, has played Harry Cunningham in BBC One's Silent Witness.
Grant's animated version of Doctor Who also starred Sophie Okonedo and future Doctor David Tennant
The Christmas special is also expected to see the debut of Matt Smith's new companion, played by Jenna-Louise Coleman.
Grant, who was born in Swaziland, has starred in films including The Player, Gosford Park and Spiceworld.
For Comic Relief's Doctor Who spoof he was cast alongside Rowan Atkinson, Hugh Grant and Jim Broadbent.
His incarnation of the Doctor described himself as "cute, sexy and lick-the-mirror handsome".
The sketch - Doctor Who and the Curse of Fatal Death - was written by Steven Moffat, who now oversees the long-running BBC One series.