Although we do not yet know who her replacement will be, Jodie Whittaker's time as the Doctor in Doctor Who is rapidly coming to an end. With just two specials left before she and showrunner Chris Chibnall exit the series this year, there is, of course, vast speculation as to who Whittaker's replacement will be.

While we do not yet know who will replace the actress as the Doctor, we do know that Whittaker has filmed her part of the regeneration scene. In a recent interview with Entertainment Weekly, Whittaker opened up about how emotional filming the regeneration scene was.

"I've shot my version of regen, and it was singularly the most emotional day on set I think I've ever had," says Whittaker. "It's a really bizarre feeling, because it's the best time I've ever had on a job, and I made the decision to leave it, so it's a really strange thing to do to yourself. It feels like you're giving yourself stitches — like, 'Why have you done it?' But… it felt right."

"It was a wonderfully-celebratory-slash-grief-ridden day that I could spend with the family that I'd made. I suppose the best thing about it is that the episodes are still on," she continued. "So until they're off, I don't have to really get my head around the fact that it's not my part!"

Regeneration scenes are not filmed with both versions of the Doctor necessarily. Whittaker, for instance, did not shoot her half of the regeneration to her version of the Doctor until long after Peter Capaldi had shot his half.

Doctor Who Uses Regeneration to Change Actors

Whoever replaces Jodie Whittaker will become the Fourteenth Doctor. (Fifteenth, technically, with John Hurt's War Doctor) In Doctor Who, the Doctor "regenerates" any time the character would otherwise die. It is used whenever the actor playing the Doctor leaves the show.

Originally, Doctor Who had no concept of regeneration, but it became necessary when the first actor to play the Doctor, William Hartnell, was asked to leave the show due to his failing health and his strained relationship with the producers. Rather than cancel the show, which had already become incredibly popular, they designed a method of changing the actor. However, it was not formally referred to as "regeneration" until the end of the Third Doctor's time in the TARDIS.

Over the years of the long-running show, regenerations have become events and fans look forward to seeing how the new Doctor will be introduced. There are also the running jokes for the regenerations, such as the fact that the Doctor would like to be a ginger when he regenerates and yet never manages to be one.

Only time will tell who will replace Whittaker in the TARDIS and how the regeneration from the Thirteenth to the Fourteenth Doctor will be handled.

Doctor Who airs on BBC and BBC America. It is available on HBO Max for those without cable, although it is a full season behind the BBC.