In Doctor Who's third and final 60th anniversary special, we witnessed a shocking bi-generation which saw us left with both a Fourteenth (David Tennant) and Fifteenth Doctor (Ncuti Gatwa). The Toymaker's machinations meant a second TARDIS was created, allowing the latter to set off on a new series of adventures.
As for Tennant's Time Lord, he decided to take a break from saving the universe after a traumatic few years which saw him lose several companions and learn about his (controversial) status as the Timeless Child.
In the closing moments of "The Giggle," the Fourteenth Doctor sat with Donna Noble's family - and returning companion Mel Bush - and seemed content with going on the odd trip through time while enjoying a normal life on Earth with a family he now considers his own.
The assumption has been that the Doctor is living with Donna or Mel but the novelisation of the episode, penned by regular Doctor Who scribe James Goss, makes a surprising revelation.
It turns out that's the Doctor's house; yes, he's settled down with his own place in the countryside!
The book goes on to explain that UNIT has kept a bank account in the Doctor's name ever since he started working for them in his Third iteration, played by Jon Pertwee. As a result, he's now quite wealthy and seems content to settle down just as he once did as "John Smith."
"Bi-generation, we discover, is an ancient myth of the Time Lords where, instead of a new body taking over from the old body, the new body separates from the old body, and both are left alive," Russell T Davies previously said of the Doctor's new status quo.
"Bi-generation is a new thing; it’s the 60th," he continued. "Imagine how much fans love new things, and really rejoice when this happens [Laughs]."
"Actually, I’ve had this idea for years. I’ve always wanted, instead of going back and meeting old Doctors, I’ve always wanted the Doctor to talk to his new version. Why has it never been done before? How can you resist the two of them having an adventure at the same time?"
Davies would later hint that this didn't just affect the Fourteenth Doctor, it affected all the Doctors' previous regenerations. He'd go on to tease, "the creation of the ‘Doctorverse’ in the moment of [Fourteen's bi-generation. It’s much bigger than you think, and I hope it could lead to all sorts of things."
Doctor Who returns with new episodes this May.