Rhinestone is a 1984 20th Century Fox comedy motion picture starring Sylvester Stallone and Dolly Parton. Other members of the cast include Richard Farnsworth, Ron Leibman, Tim Thomerson, Stephen Apostle Pec, and Penny Santon.

Jake Farris (Dolly Parton), a country singer stuck in a longterm contract performing at a sleazy urban cowboy nightclub in New York City, boasts to the club’s manager Freddy (Ron Leibman) that she can make anybody into a country sensation, insisting that she can turn any normal guy into a country singer in just two weeks.

Freddy accepts Jake’s bet, putting up the remainder of Jake’s contract (if she wins the bet, the contract becomes void; if she loses, another five years will be added). He then ups the ante: if Jake loses, she must also sleep with him. The problem is that Freddie can select the man, and he chooses an obnoxious New York cab driver named Nick Martinelli (Sylvester Stallone).

Nick not only has no musical talent whatsoever, he claims to hate country music “worse than liver”. Realizing she is stuck with Nick, Jake takes him back to the hills of Tennessee for a two-week crash course in how to walk, talk and sing like a genuine country star.

Summary via Wikipedia.