According to Life Doctor Who and Combom, Matt Smith has confirmed that he’ll still be the Doctor at the end of Doctor Who‘s 50th anniversary special, and will still be the Doctor in the 2013 Christmas special and Series 8. So you can breath a sigh of relief, if you were worried.
Frankly it seems to me that the 50th anniversary show already has enough on its plate with the hints with a returning Doctor and companion and the indications that it’ll resolve the hints that showrunner Steven Moffat has been dropping since he took over the show: that the Silence will fall when the question is asked, and that question is “Doctor who?” Throwing a regeneration in there would simply be too much to fit, and casting would undoubtedly already have begun for the twelfth Doctor.
However, everybody knows that Doctor Who is going to be pulling out the big guns, spectacle-wise, for its 50th anniversary, and there’s one thing the show does that’s guaranteed to be a spectacle every time: a regeneration. While Matt Smith has never really indicated that he’s getting tired of the Doctor, he has occasionally been slow to confirm that he’s not leaving, and also talks not-infrequently about how eventually he’d like to make a go of it in Hollywood on the fame Doctor Who has brought him as an actor. To a fandom, and those who report on entertainment news, this is often the fuel of rumors. So I probably shouldn’t be surprised that rumors of the Eleventh Doctor’s regeneration happening along with the 50th reunion have run as a quiet undercurrent beneath the secrecy shrouded special, which may become less secret as it starts filming soon.
Hopefully as the latest issue of the Radio Times is disseminated, those rumors will die down.