Doctor Who has only been played by David Tennant
Doctor Who . Twelve actors have headlined the series as the Doctor . The current lead , Peter Capaldi , took on the role after Matt Smith 's exit in the 2013 Christmas special `` The Time of the Doctor '' . Doctor Who (series 10) . The series introduces Pearl Mackie as Bill Potts , the Doctor 's newest travelling companion , and also features Matt Lucas as Nardole , who appeared in the 2015 and 2016 Christmas specials .