Typecasting

In 1964, a Dalek mutant expressed his worries at the bar in The Resting Ham that the BBC would contribute to him being typecast as the inside of a Dalek by not calling him back after his audition for the role of third Aztec from the left at execution. (NOTVALID: Doctor Who? 188)

A companion of the Doctor's who had appeared for three seasons was once invited to lunch by a director. One of the options available to them was to quit before they became typecast in the role. (NOTVALID: So You Think You'd Make A Good Companion For Dr Who!)