Doctor Who Doctor's nature, somewhere between the twelfth and final incarnation. On rare occasions, other actors have stood in for the lead. In "The Five Doctors", Richard Hurndall played the First Doctor due to William Hartnell's death in 1975; 34 years later David Bradley similarly replaced Hartnell in "Twice Upon a Time". In "Time and the Rani", Sylvester McCoy briefly played the Sixth Doctor during the regeneration sequence, carrying on as the Seventh. For more information, see the list of actors who have played the Doctor. In other media, the Doctor has been played by various other actors, including Peter Cushing in
The Sixth Doctor: The Last Adventure of "Time and the Rani", but due to the firing between seasons of Sixth Doctor actor Colin Baker, the episode gave the event very little screen time and didn't explain what had caused it. Big Finish Productions producer David Richardson approached Baker in 2014, after seeing "The Time of the Doctor", which had depicted (on television) the regeneration of the Eleventh Doctor into the Twelfth: "I felt very strongly that regeneration stories, and each Doctor’s final end, are very important to "Doctor Who" fans – these are stories that allow us to see the Doctor at his most courageous, making