Former Mistresses actress Orla Brady will be guest-starring in the Doctor Who Christmas special called The Time of The Doctor which will be shown on BBC1 Christmas Day.
Orla plays an old friend of the Doctor in Matt Smith's last adventure as the Time Lord - his Doctor will be regenerating into Peter Capaldi's Doctor in what's sure to be an emotional ending.
The Doctor faces a huge mission this Christmas which will also take him back to Trenzalore, the mysterious planet housing the Doctor's grave.
Orbiting a quiet backwater planet is the massed forces of the universe's deadliest monsters including The Silence, Cybermen, Daleks and Weeping Angels have gathered, drawn to a mysterious message that echoes out to the stars. The Doctor finds himself slap bang in the middle of all these dangerous foes.
Rescuing Clara from a family Christmas dinner, the Time Lord and his best friend must learn what this enigmatic signal means for his own fate and that of the universe...
"I'm really excited about Christmas,' says Matt. "I think Steven Moffat has written a real belter for me to go out on and I had a great time filming it."
