Raquel Welch was inside the Doctor's TARDIS when the First Doctor left London in November 1963 and travelled to one million BC with Susan Foreman, Ian Chesterton and Barbara Wright.
After attempting to escape from the Tribe of Gum multiple times the Doctor told them that while he could not give them the secret of fire he did have something that could warm them up a bit: Welch. She happily left the Doctor's side to live with the tribe and as he departed she asked them where the local hairdresser was because of the messy state of her wig. (NOTVALID: An Unearthly Child: The Unscreened Edition)