Change can be hard for anyone, no matter how many times you’ve done it. Especially when that change is downright revolutionary and changes the course of history. Because those are the stakes at the heart of the Doctor Who Christmas special, which will see Peter Capaldi regenerate into the first-ever female Doctor (to be played by Broadchurch‘s Jodie Whittaker). But because life is all about balance and filling in plot holes, it looks like we’re also going to see the regeneration of the First Doctor as played by David Bradley, if the trailer for released at San Diego Comic-Con on Sunday afternoon is any indication.

But don’t just take our word for it — watch it right here, right now:

Titled “Twice Upon a Time,” the special will see both Doctors grappling with regenerating despite wanting to do so. In the end, according to the panel, both iterations of the Doctor realize they have to convince themselves in order to actually do it. (Which sounds like outgoing showrunner Steven Moffat’s way of trying to convince the many misguided fans upset about the change of the two-hearted, space-and-time-traveling alien from male to female.)

Also slated to appear in the episode is Pearl Mackie’s Bill, who will also be exiting the series alongside current Doctor Peter Capaldi, and Mark Gatiss, a frequent writer on Who and Moffat collaborator (Sherlock).

The clip looks thrilling, but if you’re looking for a few more feels, they also released a farewell video for Capaldi’s run before Whittaker and new showrunner Chris Chibnall take over next season.

Thank you, Doctor. #DoctorWho pic.twitter.com/2zFGYYx8ZL

— Doctor Who BBCA (@DoctorWho_BBCA) July 23, 2017

We’ll have more from the panel later, so keep it locked to Nerdist for our own in-house Whovian Kyle Anderson’s write-up of the event.

What do you think of the Christmas special? Let us know in the comments below!

Image: BBC America

Alicia Lutes is the managing editor of Nerdist, host of Fangirling!, and frequent over-user of Twitter dot com.