The Body Beautiful(1953)

Susan Morrow, the secretary to Robert Clarke, a model photographer, is upset when her boss pays too much attention to model Noreen Nash. Morrow's younger sister takes a candid photo of her sister in her underwear, with face hidden, and sends it to Clarke. He is intrigued and tries to locate the mystery girl but, meanwhile, enters the photograph in a contest. It wins, provided Clarke can identify the girl. He offers a reward and hires a friend to search for her. Meanwhile, back the agency, Nash offers to pose as the missing girl, but she and Clarke quarrel and she walks out. Rather than leave her boss in a fix, Morrow admits she is the girl in the picture.