The Next Doctor Press Release

The BBC Press Office have released the following details about the Doctor Who Christmas Special, The Next Doctor.
David Tennant, David Morrissey and Dervla Kirwan star in Russell T Davies's Christmas episode of Doctor Who, as two doctors combine forces in a bid to defeat Miss Hartigan and the Cybermen. Doctor Who At The Proms, a musical odyssey through time and space, hosted by Freema Agyeman, can also be seen over the festive period.
It's Christmas Eve in 1851 and Cybermen stalk the snow of Victorian London, in this special Christmas edition of Russell T Davies's Bafta Award-winning time-travelling drama.
When the Doctor arrives and starts to investigate a spate of mysterious deaths, he's surprised to meet another Doctor, and soon the two must combine forces to defeat the ruthless Miss Hartigan. But are two Doctors enough to stop the rise of the CyberKing?
David Tennant stars as The Doctor, David Morrissey as The Doctor and Dervla Kirwan as Miss Hartigan. This episode also features Velile Tshabalala as Rosita.