Years ago a father remarried and then made a will when his new wife became pregnant: leaving his fortune to his hoped-for son and failing a son to his eldest daughter (by his first marriage). When a daughter is born, he is deceived as his wife brings her up disguised as a boy called Warren. When Warren comes of age he needs to remove those who know the family secret. He creates Emily the murderess.
Joan Marshall played Warren in both his guises. Her blonde hair was shorn and dyed black, her eyebrows thickened and her mouth changed with dentures to play the young woman known to the world as Warren. She also suffered the indignity of not appearing in the credits: to keep the audience unsure about her sex, she was billed as Jean Arless.
If you look closely you can see the cheats in the scene where Emily reveals herself as Warren: her eyebrows are neither as thick as Warren’s nor as light as Emily’s.
Ben Lane was the makeup artist.