Doctor Who
Thirteen actors have headlined the series as the Doctor. The transition from one actor to another is written into the plot of the show with the concept of regeneration into a new incarnation, a plot device in which a Time Lord "transforms" into a new body when the current one is too badly harmed to heal normally. Each actor's portrayal is unique, but all represent stages in the life of the same character. Together, they form a single lifetime with a single narrative. The time-travelling feature of the plot means that different incarnations of the Doctor occasionally meet. The Doctor is currently portrayed by Jodie Whittaker, who took on the role after Peter Capaldi's exit in the 2017 Christmas special "Twice Upon a Time".
History of Doctor Who
It was announced on 4 August 2013 on a live BBC special entitled "Doctor Who Live: The Next Doctor" that Peter Capaldi would portray the twelfth incarnation of the Doctor in 'Doctor Who'. During his appearance in the special, he said that he had been a fan of the series; a letter that he had written to the Radio Times at the age of 15 about the show was read aloud. Capaldi had already appeared in the series 4 episode "The Fires of Pompeii" as Caecilius, the father of the family that the Doctor saves from the eruption of Mount Vesuvius. He had also appeared in "" as the civil servant John Frobisher.