Watch the trailer here:
Yep, the super-old 1st Doctor and the slightly less-old 12th Doctor meet in a time-stopping World War One adventure. Wonder if they'll be friends?
There's also 2 TARDIS-ES... Or is that 2 TARDI? Does anyone know what the plural of TARDIS is?
It's the Christmas special so they might even drop some hints about the new series. Hopefully we'll get to see some of the newest Doctor, the awesome Jodie Whittaker! Step aside, grand-dads!
And we're very excited about that. Here's that big reveal: