Shara Betomax

From Tardis Wiki, the free Doctor Who reference

Shara Betomax was an actress. She had performed in The Empress Magdalene and had played the character of Noon Speranza in another production.

She was cast as The Hand of Meg in The Saga of the Time Lords. At one point she was replaced with an Auton duplicate of herself, but having remained idle in anticipation of a Time Lord for so long her desire to complete the show had overridden what she was originally programmed for. After an encounter with Rose Tyler and the Doctor, she stayed on Masque Magestrix hoping she could find the original cast and crew that the Autons had replaced, unaware she herself was one. (PROSE: He's Behind You)