Diane Chambers is a fictional character in the American television situation comedy show Cheers. Portrayed by Shelley Long, Diane appeared as a show's main character up until its fifth season finale, "I Do, Adieu". She also appeared as a guest character in the series finale, "One for the Road", and in three episodes of the Cheers spin-off Frasier. Throughout her time on the program, Diane has an on-off relationship with the womanizing bartender Sam Malone (Ted Danson) and a one-year relationship with Frasier Crane (Kelsey Grammer).