Out of Sync (2000)

What you see isn't necessarily what you hear.

Roger Deacon, a down-and-out record producer, is given the job of making a singing star out of an industry mogul's girlfriend, an attractive but talentless starlet. He discovers a housewife with a powerful singing voice and decides to secretly use her to lip sync the other woman's voice for record recordings as a path to fame for her and him.