Steven Moffat has revealed that the Doctor is on his 13th and final incarnation in The Time of the Doctor.

The meta-crisis Tenth Doctor and War Doctor regenerations have meant that Matt Smith’s Doctor has now used up all of his lives.

Moffat told the Radio Times: “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?”

Only last month Moffat was telling us “The numbering stays exactly the same – and we call Peter Capaldi the Twelfth Doctor.”

Confused yet?