Cat Ballou is a 1965 American western musical comedy film starring Jane Fonda and Lee Marvin, who won an Academy Award for Best Actor for his dual role. The story involves a woman who hires a notorious gunman to protect her father's ranch, and later to avenge his murder, but finds that the gunman is not what she expected. The supporting cast features Tom Nardini, Michael Callan, Dwayne Hickman, and singers Nat King Cole and Stubby Kaye, who together perform the movie's theme song, onscreen, throughout the film.
The film was directed by Elliot Silverstein from a screenplay by Walter Newman and Frank Pierson adapted from the 1956 novel The Ballad of Cat Ballou by Roy Chanslor, who also wrote the novel filmed as Johnny Guitar. Chanslor's novel was a serious Western, and though it was turned into a comedy for the movie, the filmmakers retained some darker elements. The film references many classic Western films, notably Shane. The film was selected by the American Film Institute as the 10th greatest Western of all time in its AFI's 10 Top 10 list in 2008.
(Summary from Wikipedia)