The Doctor has the gift of regeneration into new lives.
The Doctor (Doctor Who) . The transition to each succeeding actor is explained within the show 's narrative through the plot device of `` regeneration '' , a biological function of his race that allows their change of cellular structure and appearance with recovery following a potentially fatal injury . The incumbent Doctor is the Twelfth Doctor , played by Peter Capaldi , who succeeded Matt Smith in the role in the 2013 Christmas special `` The Time of the Doctor '' after he was granted a new `` cycle '' of regenerations by the Time Lords . The War Doctor and an aborted regeneration are counted in his previous cycle of twelve regenerations .