The Doctor is a fictional alien.
Sarah Jane Smith is a fictional character played by Elisabeth Sladen in the long-running BBC Television science fiction series Doctor Who and two of its spin-offs . The Doctor is the title character and protagonist in the long-running BBC science fiction television programme Doctor Who . The Time Lords are a fictional , ancient extraterrestrial people in the British science fiction television series Doctor Who , of which the series ' protagonist , the Doctor , is a member .