A cast list was released for the Doctor Who BBC centenary special, The Power of the Doctor.

Composite synopsis:

A bullet train comes under attack on the edges of a distant galaxy. Some of history’s most iconic paintings have gone missing and have been defaced. Seismologists from 21st century Earth disappear without trace. The court of Tsar Nicholas II falls under a malign influence of the mesmeric Rasputin in 1916 Russia. A Dalek makes contact with the Doctor. These strange incidents draw the Doctor to her last stand against the combined forces of the Daleks, the Cybermen and the Master in a battle for her very existence.

Along with Jodie Whittaker (the Doctor), Mandip Gill (Yaz), John Bishop (Dan), Sacha Dhawan (The Master/Rasputin), Sophie Aldred (Ace), Janet Fielding (Tegan), Jacob Anderson (Vinder), Jemma Redgrave (UNIT chief Kate Stewart), Patrick O’Kane (Lone Cyberman Ashad), and Nicholas Briggs (Voice of the Daleks and Cybermen), some additional cast members and character names for the special were released.

Richard Dempsey
Dempsey plays Nicholas, likely Emperor Nicholas II of Russia.

Anna Andresen
Andresen plays Alexandra, likely Empress Alexandra of Russia.

Sanchia McCormack
McCormack plays Train Marshal Halaz, likely on the bullet train

Joe Sims
Sims plays Deputy Marshal Arnhost, likely on the bullet train

Danielle Bjelic
Bjelic plays a curator, likely in the museum Ace visits.

Jos Slovick
Slovick plays a messenger.

For spoilers about appearances of other Doctor Who characters who will likely appear in The Power of the Doctor, you can look here and here.

Written by Chris Chibnall and directed by Jamie Magnus Stone, the Doctor Who BBC centenary special, The Power of the Doctor airs 23 October, 7:30pm on BBC One.