Sam Malone and Diane Chambers, collectively known as Sam and Diane, are fictional characters in the American sitcom television series Cheers. Sam is a working-class, baseball player–turned–bartender played by Ted Danson; Diane is a college-graduate cocktail waitress played by Shelley Long. Danson appeared on Cheers for its entire run of the series; Long was part of the regular cast from the 1982 series premiere ("Give Me a Ring Sometime") until the fifth-season finale, "I Do, Adieu" (1987). Long returned for a special appearance in the 1993 series finale, "One for the Road."
During the first five seasons, Sam and Diane both flirt with and condemn each other as social opposites, repeatedly consummating their relationship and breaking up. When they are not together, Sam has affairs with many women; Diane has relationships with men fitting her upper-class aspirations, such as Frasier Crane (Kelsey Grammer), a long-running character who initially debuts in the third season as Diane's love interest in the romantic pair's dynamic. Each of the first four season finales ends with a cliffhanger involving the story arc. In "I Do, Adieu" (1987) Sam and Diane are due to marry, but they cancel the wedding when Diane leaves Sam and the bar to begin a career as a writer. In the series finale Sam and Diane are reunited, become engaged and break up again, realizing that they are never meant to be together.
The pairing of Sam and Diane has evoked mixed reactions. Some critics disliked the relationship, either for alienating viewers by dominating the show (and removing its original premise) or because they saw Sam and Diane as a mismatch. Others praised the pair, seeing them as strengthening the show. Some writers compared them to couples in later shows, such as Moonlighting, with their sexual tension and intermittent relationships.