We still don’t know much about what to expect from the next Doctor Who adventure to hit our screens, a festive special due to broadcast this Christmas – but at least now we know the reason why.

This week Doctor Who head writer Steven Moffat revealed that work on this year’s special was only just beginning, taking place after the filming of around four series 10 episodes despite those stories not airing until much later (around April, as it turns out). So the reason no information had been announced is because there was no information. Simple.

But you may now be asking yourself, why was the filming staggered in this way? Why not film the Christmas special before the next series (as is usually the practice), instead of jumping ahead when there’s no real need to?

Well, there are a few possible explanations. One is that special location filming (including trips to Spain) was needed for the 2017 episodes, which were time-consuming and more pressing than the Christmas episode (which might involve less travel). Alternatively, it could just be that it worked out this was the most efficient schedule – the Christmas special normally films around this time of year, so perhaps they thought they might as well just fit the rest of the series’ shooting around it.

Both of these or neither could be true (the fact that four entire episodes have been filmed rather than bits of several doesn’t seem to suggest targeted location work) – but either way there could also be a hidden motive behind the unusual schedule.

You see, back in 2009 when filming Matt Smith’s first series of Doctor Who, the production staff decided to shoot a few of his later episodes first (The Time of Angels/Flesh and Stone to start) so that he could really get a handle on the character, shooting his first story The Eleventh Hour later on when he’d really “warmed up” as the Eleventh Doctor.

Could it be this new back-to-front schedule is an echo of this, allowing another series newcomer to adjust to a major role before making a good impression in their first appearance? In other words, could we be seeing the first appearance of new companion Pearl Mackie this Christmas?

Sure, it has previously been stated that Mackie’s character Bill won’t appear this Christmas, but that could just be a smokescreen for her to make her big entrance – and in any case, plans could have changed since those statements were made. Jenna Coleman’s Clara was one of the series’ longest-running companions, after all, so producers would want Mackie at the top of her game to convince fans she could fill her shoes.

And the more we think about it the more this makes sense – Mackie is already on set and filming episodes, so it’d be easy for her to slip into the special (perhaps alongside fellow companion Matt Lucas, whose character Nardole could be appearing in both the Christmas special and 10th series as well). If she’s left out, the actress would be left twiddling her thumbs for weeks while the Christmas episode shoots.

Plus, considering fans have already been introduced to the character with an announcement scene earlier this year, it would make sense for that momentum to be continued by properly introducing the character this December, rather than welcoming a one-off companion who’d leave within the same episode. Fans want to see more of Bill, and making them wait until April to do so could be a missed opportunity.

Of course it could be that we’re reading too much into this, and that there are perfectly legitimate organisational reasons as to why filming has been done in this way. But even if that’s true, it’s still created a perfect opportunity for Pearl Mackie to make her debut this year – and if we don’t see her in at least one small cameo this Christmas, we’ll eat our Santa hats.

Doctor Who will return to BBC1 this Christmas, and in Spring 2017 for a full series