The news was confirmed rather casually as Gatiss partook in an interview with Empire magazine at Comic Con, alongside Capaldi and Steven Moffat. Watch the interview below: The news is revealed around the 11:30 mark.
But of course Gatiss’s most recent contribution to the Whoniverse was the aforementioned Ice Warrior episode Empress of Mars, which he had previously suggested could be the end of his Doctor Who career.
“I’ve no idea,” he told RadioTimes.com a few months ago when asked whether he would continue writing for Doctor Who when new showrunner Chris Chibnall took over. “It’s a funny thing, an end of an era.
“Obviously working very closely with Steven I feel it more than when Russell [T Davies, previous showrunner on Doctor Who] left. I suppose there was more of a sense of continuity there, but I’ve no idea,” he added.
“I’ve had a fantastic run on my favourite show, so if I don’t do anymore then I’m perfectly sanguine. But who knows?”
Who knows indeed – because clearly, longtime creative partner Steven Moffat (with whom Gatiss created fellow BBC series Sherlock and future project Dracula) couldn’t bear to write his last episode without having his old pal around in some form, giving Gatiss one last crack of the Whoniverse whip.
And even if this episode finally is the end of Gatiss’ Who experience, this new role will definitely make him one of the people with the longest and most complicated entries on the Doctor Who wiki page after the festive special airs – and in the end, isn’t that what it’s all about?
Sign up to the Radio Times newsletter for the latest TV and entertainment news