It was Jan Rubes' performance in Dead of Winter that lead to him being cast as Andreas.
Lydie Denier said in an interview that while filming the scene where she strips naked and goes to kiss Ray Walston's bedridden character, Walston looked at her and suddenly couldn't remember his dialogue. He told her, "That's the first time I ever forgot my lines!" Denier took that as a huge compliment.
Robert Stack was originally slated to play Andreas.