As you probably know, David Tennant, Russell T Davies, Julie Gardner and John Barrowman are currently at Comic Con, and this very interesting piece of information has been posted on Digital Spy:
"Cut to brief preview reel of clips from David's final episodes as the Doctor. A voiceover mentions "bad dreams". Shots of Wilfred and Donna, and a man wearing a black hood. "His name is the master," says the voiceover and John Simm is revealed (with blond hair). "He returns". Final caption says: "The end of time. Christmas 2009."
Eep. Am I the only person desperate to see this clip?!