'Doctor Who's Russell T. Davies explains surprise regeneration & when we'll see the 15th (!?) Doctor

Over the weekend, Jodie Whittaker's time as the Thirteenth Doctor came to an end in The Power of the Doctor, a finale special that told Whittaker's final story in the TARDIS, and set the stage for what's to come in Doctor Who's 60th anniversary next year. 

By now, Doctor Who fans are used to what comes at the end of a Doctor's run on the show. Each Doctor gets a moment to reflect, to say a few final words, and then their Time Lord biology takes over, regenerating them into the form of the next actor who'll take on the role. But in The Power of the Doctor, something rather shocking happened when Whittaker's Doctor lit up with the golden light of regeneration. 

**SPOILERS AHEAD for The Power of the Doctor**

At the beginning of the regeneration scene, everything seemed to be going normally for Thirteen's last moments. She stepped out of the TARDIS and onto a cliff overlooking an ocean, mused over how sad it was that she wouldn't get to see what happens next, then offered a welcome of "Tag, you're it" to "Doctor whoever I'm about to be." Regeneration took over, and at the end of the process she became...

...David Tennant.

That's right, Whittaker's Thirteenth Doctor regenerated into the guise of Tennant's Tenth Doctor, who is now officially, according to a BBC press release, also the Fourteenth Doctor. To quote Ten/Fourteen: "What?!"

That's the big question, and one that will be answered next year when Doctor Who returns for a round of specials to celebrate its 60th anniversary under the leadership of returning showrunner Russell T. Davies, the man responsible for giving us Tennant in the TARDIS to begin with. Speaking to The BBC about the surprise reveal, Davies had only this to say by way of explanation:

"Maybe this is a missing story. Or a parallel world. Or a dream, or a trick, or a flashback. The only thing I can confirm is that it’s going to be spectacular, as two of our greatest stars reunite for the battle of a lifetime.”

Yes, Davies said "two of our greatest stars," as fan-favorite Catherine Tate will also return to reprise the role of Donna Noble, as she and The Doctor take on a new villain played by none other than Neil Patrick Harris. But what does all of this mean for the man announced as the next Doctor earlier this year, Sex Education star Ncuti Gatwa? According to The BBC's press releases surrounding The Power of the Doctor, Gatwa is now officially known as "The Fifteenth Doctor," and did get to appear briefly in a teaser for next year's special, appropriately demanding "Someone tell me what the hell is going on here!" You can check out that teaser, including some brief bits of Doctor Who action, below.

So, how does Gatwa take over from Tennant? Does he take over from Tennant? How are Tennant and Tate back at all? Why is there an entirely new actor playing Rose? 

“If you thought the appearance of David Tennant was a shock, we’ve got plenty more surprises on the way," Davies said. "The path to Ncuti’s Fifteenth Doctor is laden with mystery, horror, robots, puppets, danger and fun! And how is it connected to the return of the wonderful Donna Noble? How, what, why? We’re giving you a year to speculate, and then all hell lets loose!”

Doctor Who returns in 2023 with three new specials. 

Looking for more sci-fi adventure with a dash of time travel? Check out SYFY's Resident Alien, streaming now on Peacock.