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".
Jodie Whittaker
On 16 July 2017, the BBC announced that Whittaker would become the thirteenth and first female incarnation of The Doctor in the British TV series "Doctor Who". She formally assumed the role from Peter Capaldi in the 2017 Christmas special episode "Twice Upon a Time" when Capaldi's Twelfth Doctor regenerated into Whittaker's Thirteenth Doctor. Whittaker appears in her first full series as the Doctor in the eleventh series, which premiered in October 2018. She is set to continue in the role in the twelfth series in 2020.