 The following tables are an overview of all the regular cast members that have appeared throughout the show since 1963.William Hartnell, Carole Ann Ford, William Russell and Jacqueline Hill first appeared as the Doctor, Susan Foreman, Ian Chesterton and Barbara Wright respectively in the show's debut serial; "An Unearthly Child".Ford departed in "The Dalek Invasion of Earth" in 1964 and was replaced by Maureen O'Brien playing a character called Vicki.