The Doctor (Doctor Who) Big Finish Productions. Matt Smith made a brief "imagined" cameo seen only by actor William Hartnell (portrayed by David Bradley), in the movie dramatising the early years of Doctor Who "An Adventure in Space and Time". In early production documents, the Doctor was said to be 650 years old, although this was never stated on screen. By the time the Doctor did cite his age ("Let me see, in human terms, 400, yes, 450 years" in the serial "The Tomb of the Cybermen" (1967); he kept a 500-year diary), he had already regenerated to a younger form. The intention at
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