The silence around the Doctor Who Christmas special has become almost eerie.

Peter Capaldi and new companion Pearl Mackie are deep into filming on series ten – which is not due to air until 2017 – and yet the BBC have fed us location shots, episode details and news of guest-stars. Meanwhile, enthusiastic fans have, as usual, been sharing their own snaps from the set.

But when it comes to the festive episode – airing in just a few months and surely in the can by now – there’s been nothing. No official announcements – and no leaked photos either, which is particularly unusual.

There are a few possible explanations for this (which we go into in further detail here). One is that Mackie – slated to make her debut in the new series – is actually going to turn up as an early Christmas present, having shot her scenes (including one involving some suspiciously snowy backgrounds) while working on the full series. Another is that Jenna Coleman’s Clara Oswald could make a brief return in a companion-lite episode, having filmed an additional piece with Peter Capaldi not long after bowing out.

But here’s another option: what if the Doctor Who Christmas episode is actually a crossover with new BBC3 spin-off show Class – or at least a further introduction to one or more of its characters?

Class follows the pupils (and at least one teacher) at Coal Hill School, which has featured in Doctor Who numerous times down the years – from the very first episode, when the Doctor’s granddaughter Susan went there, to some 50 years later, when it was the workplace of a certain Miss Oswald. All that timey-wimey business “has caused the very walls of space and time to become thin”, so we can expect enough time travel-based shenanigans and alien encounters to make the Doctor lick his lips.

Class launches in the BBC3 section of iPlayer sometime in October and will initially consist of eight episodes, expected to become available weekly. Which means a late October premiere would put the final instalment smack in the middle of December, with just a week or two to go until Christmas Day. A Christmas Doctor Who crossover would therefore follow on very nicely indeed, reintroducing the Doctor after that long hiatus and potentially carrying on the story of the Class kids.

Actually, though, Christmas may not be the first time we see the Doctor in action this year. The initial synopsis for Class promised an appearance from a “legendary figure out of space and time” and when we asked showrunner Patrick Ness whether the Twelfth Doctor might make an appearance, he teased “I can neither yet confirm nor deny… But I’m a big Peter Capaldi fan, let’s put it that way”. A source close to the production later went one better, telling us Class “will have a close connection with Doctor Who so don’t be surprised if Peter pops up”.

Basically, there’s going to be a Doctor Who crossover episode of Class, so why not the other way around?

There are plenty of reasons this would make sense from the BBC’s point of view. Doctor Who fans weren’t exactly ecstatic when it was announced that the main show would skip 2016 and they wouldn’t get a new series for a year and half.

And since BBC3 went online and had its budget slashed, new drama has been at an increasing premium – it needs to do well. So we find ourselves in a situation where Doctor Who needs to placate fans and BBC3 needs Class to perform.

What better way to do both than with a bit of cross-pollination.

If Class needs a boost, the huge audience that a Doctor Who Christmas special gets will provide that – remember, the full series of Class should be on iPlayer by then so its target audience of young adults who haven’t yet picked up on it can make it their Boxing Day binge-watch, while Doctor Who fans keen to bridge the gap until the next series will have a show made canonical by its association with the Christmas special (and almost certainly by an appearance from the Doctor).

What’s more, the traditionally broader, less fanboyish, flavour of a Christmas special would be the perfect time to do a crossover with another show – when the series returns for real, fans are going to want pure unadulterated Who.

All in all this seems like a great way to bring together the already converging worlds of Class and Doctor Who, and at the same time would explain why we haven’t had more details of the Christmas special: filming it at least partly within the confines of Coal Hill School would have helped to keep things under wraps – until we’re ready to tear them off in time for Christmas.