Some movie posters for the film featured a long text preamble that read: "They say that behind every great man there's a woman. But in this case it's ridiculous. When rich, eccentric Edwina Cutwater died, a crazy guru tried to transport her soul into the body of a beautiful young woman. But the guru goofed. And Edwina's soul has accidentally taken over the entire right side of her lawyer, Roger Cobb. He still controls what's left. Now, Edwina and Roger are living together in the same body. He's losing his job. He's losing his girlfriend. And he just can't seem to get her out of his system. No matter how hard he tries".
In an interview, Steve Martin once said of this movie: "This man is not an idiot. He is a contemporary person with some brains . . . he's not naive or a victim of circumstances. He's an intelligent man who happens to get caught in a disaster. That's a big difference between this role and any other part I've played . . . For the first time I'm in a story with a beginning, middle, and end. It's old-fashioned and solid . . . This movie was like going to school. I learned a lot about structure and character".
Both of the film's comedic leads, Steve Martin and Lily Tomlin, were nominated for the Golden Globe lead acting award in a comedy or musical for their respective real genders. Neither won but Martin was awarded the Best Actor Award from both the New York Film Critics Circle Awards and the National Society of Film Critics Awards.
According to the TCMDb, "Reportedly, the actress [Victoria Tennant] was so smitten with [Steve] Martin that on the first day of production she rushed home to tell her male roommate he had three days to move out".
The trivia item below may give away important plot points.
In common with Steve Martin and Carl Reiner's film The Man with Two Brains (1983), the story ends with the main character finally united with his female lead, who has been disembodied throughout the movie, in the body of the villain.