Multiple actors have played the role of Doctor Who
Doctor Who . Twelve 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 -- an idea introduced in 1966 to allow the show to continue after the departure of original lead William Hartnell who was becoming very ill at the time . 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 . Other returning writers who have worked on this series and previous ones include Frank Cottrell-Boyce , Sarah Dollard , Jamie Mathieson , Peter Harness , Toby Whithouse and Mark Gatiss , as well as two new writers for the revived era of the programme , Mike Bartlett and Rona Munro , the latter of whom wrote Survival , the final serial of the original classic era .