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".
Doctor Who
"Doctor Who" has appeared on stage numerous times. In the early 1970s, Trevor Martin played the role in "Doctor Who and the Daleks in the Seven Keys to Doomsday". In the late 1980s, Jon Pertwee and Colin Baker both played the Doctor at different times during the run of a play titled "Doctor Who – The Ultimate Adventure". For two performances, while Pertwee was ill, David Banks (better known for playing Cybermen) played the Doctor. Other original plays have been staged as amateur productions, with other actors playing the Doctor, while Terry Nation wrote "The Curse of the Daleks", a stage play mounted in the late 1960s, but without the Doctor.