Another Doctor for the 50th? But Who?

Could another Doctor be returning for the 50th Anniversary special of Doctor Who? Last week, Peter Davison, who played the 5th incarnation of the Doctor, has confirmed himself to be making an appearence in the special. A few days before he let it slip, he had mentioned having a script personally sent to him with his name on it. Although, this may have to do with the fact that David Tennant, who is returning as the 10th Doctor, is also married to Peter's daughter Georgia Moffat, who also had a guest role in Doctor Who - as the 10th Doctor's daughter. (Crazy, huh?)

But this wouldn't be Peter's first time returning to the show itself. He had returned to the show twice before. Bother were for charity specials aired by the BBC, including one where Peter Davison's Doctor met David Tennant's incarnation in the 10th Doctor's TARDIS! But this also begs the question - Will we see other incarnations of the Doctor, old and new, show up later on? The 50th isn't too far away, and there's still a bit more news to come, so only time will tell....