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 (series 11)
On 8 March 2018, Alan Cumming announced that he had been cast as King James I in an episode of the series. On 25 March, comedian Lee Mack stated that he would make a brief appearance in one episode. Shaun Dooley also appears in the series. In a "Coming Soon" vignette during the closing credits of the premiere episode, "The Woman Who Fell to Earth", a number of guest actors appearing in the remaining episodes of the series were shown: Mark Addy, Julie Hesmondhalgh, Shane Zaza, Shobna Gulati, Brett Goldstein, Josh Bowman, Siobhan Finneran, Lois Chimimba, Susan Lynch, Hamza Jeetooa (credited as Hamza Jeetoa), Art Malik, Suzanne Packer, Vinette Robinson, Amita Suman, Ben Bailey Smith, Phyllis Logan, and Chris Noth.