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 Chase (Doctor Who) the last appearance of Russell and Hill as companions Ian and Barbara and the introduction of Peter Purves as new companion Steven Taylor. In the TARDIS, the Doctor, Ian, Barbara, and Vicki are huddling around the Time-Space Visualiser, a television-like souvenir from their recent adventure at the Space Museum, which can pick up on any past event in the whole of time and space. The TARDIS then lands, and the Doctor confirms conditions are hospitable. Ian and Vicki leave to explore the desert wilderness. They find an ancient trap door in the sand. Inside, they are trapped — and become