The Doctor (Doctor Who) Time Lords a fixed number of twelve regenerations, meaning that every Time Lord had a total of thirteen incarnations including the original. The plot of "The Time of the Doctor" involves the Doctor receiving a new cycle of regenerations from the Time Lords before his expected demise, triggering the regeneration into the Twelfth Doctor, played by Peter Capaldi. The origins of the programme were explored in the docudrama "An Adventure in Space and Time" as part of the 50th anniversary celebrations of "Doctor Who", which starred David Bradley as William Hartnell. Although Time Lords resemble humans, their physiology differs in
Doctor Who and the Daleks in the Seven Keys to Doomsday early 1970s, and was a fan of "Doctor Who". In 2008 Big Finish Productions released "The Seven Keys to Doomsday" as an audio drama, directed by John Ainsworth. Doctor Who and the Daleks in the Seven Keys to Doomsday Doctor Who and the Daleks in the Seven Keys to Doomsday was a stage play based on the long-running British science fiction television series "Doctor Who". The play ran at the Adelphi Theatre in London, England for four weeks, beginning on 16 December 1974. Originally, the part of the Doctor was to be played by Jon Pertwee, but the role went