Spoiler (click to reveal)
These are rumors. Taken them as such until the Beeb actually confirms or denies them. Remember to take denials with a grain of salt, like how RTD denied that Kylie Minogue would be in the Christmas special for several months.
- Ben Kingsley is rumored to appear as Davros, creator of the Daleks.
- Joan Collins is rumored to appear as the Rani.
One of these two is probably false, if not both, simply because two returning villains of this scale would probably not show up in the same series.
- Peter Davison is rumored to appear in this year's Children in Need special with David Tennant, presumably as the Fifth Doctor.
- The Daleks are rumored to show up again. Of course, they keep showing up, so is it really a spoiler if they do?