Do these new Doctor Who Christmas pictures reveal a secret callback to the 50th anniversary special?

You remember – it was this scene.

Anyway, Capaldi’s appearance in the 2013 episode has never been shown in the main series since he took over the role, so some began to wonder if his final episode this Christmas would fill in that niggling plot hole. After all, the First Doctor (who also appeared in the 50th) is in the Christmas special too – so who’s to say that the episode couldn’t include the pair travelling together through time to join those events, capping off the era of showrunner Steven Moffat in grand style and also neatly tying Peter Capaldi’s final appearance in with his first?

However, as we get nearer and nearer to the Christmas episode’s debut this fan theory is looking less and less likely. Of the footage we’ve seen and information we’ve been given, nothing points towards any Day of the Doctor tie-ins – but now, some newly-released pictures from Twice Upon a Time do seem to contain a secret connection between the episodes.

Take a look at this Christmas special shot of David Bradley in the First Doctor’s Tardis. As many fans have pointed out these hexagonal wall decorations weren’t actually found in the original Tardis control room, whose walls were instead adorned with a larger, circular design.

However, while the hexagons might not be the same as the 1960s Doctor Who series Tardis, we have actually seen them before: in the closing moments of the 50th anniversary special.

In those final scenes, Matt Smith’s Eleventh Doctor meets a mysterious figure called The Curator, played by Fourth Doctor actor Tom Baker. And on the wall behind them in the gallery? Those very same hexagon roundels, albeit at a slightly different angle.

So what could this mean? Well, when The Day of the Doctor first aired many fans speculated that the gallery The Curator tended to could be some future version of the Tardis, partially based on the presence of those hexagonal decorations (which looked quite Tardis-y even then).

Now we can see these hexagons in the Christmas special – is there a connection? Maybe the Tardis kept that design in storage all this time, and accidentally gave Doctors 12 and One a sneak preview of its future Curator-based design (it’s previously been noted in the series that the Tardis already has unused control rooms ready).

Or maybe it’s more of a visual clue from Moffat and the production team that Baker’s Curator might mean more to the Doctor than first appeared, while also paying tribute to modern Who’s grandest hour (the anniversary special itself) in a more subtle way than just having the two Doctors fly off to hang out with Matt Smith et al.

Of course, maybe this is just an example of the production team merely reusing a bit of old set to help create their new 'old' Tardis. However, that would be forgetting the fact that two years ago the series actually brought back ANOTHER original Tardis – one stolen by the Doctor and Jenna Coleman’s Clara – which only had the normal, rounded wall decorations.

Surely if they WERE going to reuse old sets, that more recent example would be an easier target? Either way, why they included it – and what it could mean for the Christmas special – remains mysterious for the time being.

Doctor Who: Twice Upon a Time airs on BBC1 on Christmas Day (Monday 25th December) at 5.30pm