The Doctor is in ... again.

"Broadchurch" star Jodie Whittaker made her debut as the titular time traveler in "Doctor Who" in yesterday's BBC Christmas special. Peter Capaldi appeared for the last time as the 12th Doctor, before the character regenerated into Whittaker.

In July, Whittaker was announced as the first female Doctor in the British television show. Her casting reunites her with new "Doctor Who" showrunner, Chris Chibnall, who created "Broadchurch."

BBC released a clip of the regeneration moment, which sees Capaldi's Doctor bursting into flames and slowly revealing Whittaker (a ring slips off her finger, indicating the physical change). She sees her reflecting and murmurs, "Oh, brilliant!" — just before the TARDIS goes haywire.

The news of a female doctor was met with a mostly positive response, but some fans took issue with changing the character, who had always been male.

"I'm beyond excited to begin this epic journey — with Chris and with every Whovian on this planet. It's more than an honor to play the Doctor," Whittaker said at the time of her casting announcement. "It means remembering everyone I used to be while stepping forward to embrace everything the Doctor stands for: hope. I can't wait."