Doctor Who: David Tennant is the 14th Doctor, and fans have gone wild

Well, it's official. Jodie Whittaker's 13th Doctor bowed out in a blaze of glory in last night's feature length episode of Doctor Who. But instead of regenerating into the previously announced Ncuti Gatwa as expected, we were left with a very confused-looking David Tennant back as the 10th Doctor - or so it seemed.

"I know those teeth", Tennant's Doctor exclaimed as it dawned on him that this new incarnation isn't that new at all, before signing off with a teaser that confirmed we have to wait a full year to find out what the heck is going on.

If you've been paying attention to all things Doctor Who, you'll know that Tennant's return has been public knowledge for some time now. The actor is coming back alongside companion Donna Noble (Catherine Tate) and showrunner Russel T. Davies for the 60th anniversary in November.

It's not uncommon for previous Doctors to return for anniversary specials, of course, but few could have predicted that Whittaker would actually regenerate back into Tennant. Needless to say, fans were delighted to see Tennant back on their screens as the Time Lord.

Now, according to Davies himself, when Gatwa makes his debut next year, it will be as the 15th Doctor. This means that Tennant is officially the 14th Doctor. And the 10th Doctor. And the meta-crisis Doctor. And the 10.5th Doctor. Good lord.

“If you thought the appearance of David Tennant was a shock, we’ve got plenty more surprises on the way," the showrunner said of the shock cliffhanger. "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 will officially return to our screens in November 2023.