Original: The character of Sarah Jane, played by Sladen, appeared in Doctor Who from 1973 to 1976, alongside Jon Pertwee as the Third Doctor and later Tom Baker as the Fourth Doctor.
Simplified: The series stars Elisabeth Sladen as the journalist Sarah Jane Smith, who was a companion of the Third and Fourth Doctor in the classic Doctor Who series. Sladen played the original part of Sarah Jane from 1973 until 1976.