Most of the actors in this story had either just been in a Doctor Who, or were just about to do so, namely: Gabor Baraker, Zohra Sehgal, Walter Randall, Jean Marsh, Reg Pritchard and Bernard Kay. It was also the first story to have non-white actors in it as opposed to just painting the face. The latter was a common practice at the time. Nicholas Courtney was briefly considered as a replacement for Julian Glover and Jean Marsh would go on to play Sara Kingdom.