According to The Mirror, Jenna Coleman’s companion Clara will return for the episode, having appeared in the seventh, eighth, and ninth series.
The tenth series of Doctor Who finished with an astonishing cliffhanger, revealing the First Doctor — played by Game of Thrones’ David Bradley — would play an integral role in the multi-doctor Christmas special later this year.
“It’s become a tradition now for the companions to reappear as the Doctor regenerates and Jenna isn’t letting the side down,” one source said.
The upcoming special will mark the first time the First Doctor has appeared actively onscreen since 1983’s ‘The Five Doctors’, when the character returned to the series following his regeneration almost 20 years prior.