Watson was played by Victor Brandt. He was cast in the part thanks to John Meredyth Lucas, who had directed Brandt in an episode of The Invaders in which he had performed a scene featuring the death of his character therein. "He called me up," the actor recalled, "and said, 'I’ve got another death scene for you.'" Brandt then portrayed Watson. One aspect of his performance that stuck in his mind was that he "had to remember all this technical crap about the working of the ship."