“We’ll find out that Matt Smith is actually the 13th Doctor. Although everyone knows that the Doctor can only regenerate 12 times. The 12 regenerations limit is a central part of Doctor Who mythology – science fiction is all about rules, you can’t just casually break them. So if the Doctor can never change again, what’s Peter Capaldi doing in the Christmas Special?”
This move is presumably to finally address Doctor Who's greatest loose end and usher in a fresh new set of regenerations in the 50th year - but just how will the Eleventh Doctor regenerate if his regenerations are up?
Matt Smith will make his final bow in The Time of the Doctor, which airs on Christmas Day at 7.30pm on BBC One.
[Source: Doctor Who TV]