Doctor Who: BBC Centenary Special Trailer Breakdown - 11 Things You Must See

This has become a growing trope around Who regeneration episodes, but we have been given a slight glimpse at the Thirteenth Doctor regenerating. Do we think this is the final moment, or just an early forced version? Who knows.

A reason to maybe consider this is the Doctor's actual regeneration, is we have been told by director James Magnus Stone the regeneration was filmed outside the TARDIS, whether a misdirection or not.

If this isn't the Doctor regenerating, a major consideration to make would be this is the Doctor opening the fob watch we're introduced to in the Flux series, storing the pre-Hartnell days. Some argue leave this a secret, but if we're going to do this, end Jodie's tenure on it, rather than not answering her tenure's biggest question.

We've seen these fob watches opened before, notably Utopia, and the reinstating of memories is the result of regeneration like energy pouring out.

Either way, we know the regeneration is coming as this is Jodie's final story, but how this comes to be is obviously a secret. However, we are still given a tease of it.

It's only around six to seven months from this episode and we don't even know who's taking the TARDIS controls after, maybe we won't at the end either - War Games-style.