“The whole episode is a massive celebration and it’s kind of about celebrating the last 50 years of Doctor Who, with a massive team of us all thrown in there, but it’s quite a transformation episode and it very much changes the direction of where the show is going in quite a big way.”As well as seeing the return of David Tennant and Billie Piper as the Tenth Doctor and Rose Tyler, the anniversary will also reveal the mystery of where John Hurt's Doctor fits into the history of the show. Very little has thus far been revealed about which incarnation of the Doctor Hurt will play, with speculation veering from a future incarnation to the infamous Valeyard. However, Coleman remained tight-lipped, but she did drop a few little hints for fans to dissect as the countdown to the anniversary continues.
“He [Hurt's Doctor] is the Doctor that no one knew about. He is the Doctor that’s never talked about, not mentioned and of course we're going to explore why and that story and also see David’s Doctor and Matt’s Doctor and John’s Doctor – the three of them interacting, which is great."It seems clear that the revelation of the Doctor's past will affect the future of the show - but change was inevitable anyway, for the end of the year will see Matt Smith's departure after three series in the lead role. Coleman had plenty to say on her co-star's departure, though she insisted she still does not know who his replacement will be.
“It’s kind of unimaginable for me at the moment, but as I say the new Doctor isn't yet cast — we’re just having great fun together and enjoying the time we have left. It’s a strange thing because I always knew he was gonna be leaving so it will be kind of bittersweet. But I think possibly there’s quite a bit of denial going on."[Source: Access Hollywood]