Kellerman received her breakthrough role (Major Margaret "Hot Lips" O'Houlihan in Robert Altman's "M*A*S*H") in 1970. Her performance earned Academy Award and Golden Globe nominations, winning the Kansas City Film Critics Circle (KCFCC) Award for Best Supporting Actress, the Golden Laurel for Best Comedy Performance (Female) and a second-place National Society of Film Critics (NSFC) Award for Best Supporting Actress. Kellerman was featured in "Life" magazine. She again collaborated with Altman in "Brewster McCloud" as Louise, guardian angel to Bud Cort, and recorded "Rock-a-Bye Baby" for the film's soundtrack.