 Breck Stewart was cast in this movie a few days after he won the  lead role in Say Uncle. Since the arrangements for his stay in San  Francisco had already been set in advance for Say Uncle, Stewart had  to fly to San Francisco to shoot his scenes, come home in his native  country for a few days and go back to film his scenes for Natural  Instinct which were shot in a nearby location. He could have stayed  in San Francisco the whole time but the budget didnt allow to pay  for his accommodations and he decided to make the two trips in rapid  succession instead.