The singing voice of Natalie Wood in West Side Story, Audrey Hepburn in My Fair Lady and Deborah Kerr in The King and I has died. Marni Nixon, the best known of Hollywood’s ghost singers, dies of breast cancer Sunday in New York. She was 86.

Nixon, an acclaimed concert singer who soloed with the New York Philharmonic and played New York’s top halls before heading to Hollywood, was heard on million-selling soundtrack albums singing standards such as “Getting to Know You” and “I Could Have Danced All Night.” Her voice could also be heard, uncredited, in Mary Poppins and Cinderella. In all her studio jobs, she was paid a flat fee and contractually told to not disclose her identity; she started expressing her dissatisfaction with the set-up in interviews in 1967.

Nixon sang for Ingrid Bergman in Joan of Arc, did Kerr’s nightclub singing in An Affair to Remember and hit the high notes for Marilyn Monroe in Gentlemen Prefer Blondes.

Born in Altadena, she won a vocal competition at the Los Angeles County Fair as an 11 year old and studied with the Austrian soprano Vera Schwarz. At 17, she sang in Orff’s Carmina Burana with the Los Angeles Philharmonic. She would go on to record music by Schoenberg, Stravinsky, Webern, Ives, Aaron Copland, George Gershwin and Jerome Kern, receiving two Grammy nominations for her classical works.

As a teen, she worked as a messenger at MGM and the studio booked her to sing for young actresses in the 1940s and ‘50s. She did step into the legit theater’s footlights in 1964, playing Eliza Doolittle in My Fair Lady at City Center in New York.

In the 1980s and ‘90s, she toured in a one-woman show Marni Nixon: The Voice of Hollywood, appeared in Off Broadway shows and in operas. She return to Broadway in the early 2000s in James Joyce’s The Dead, Nine and Follies.

Her son, the singer-songwriter Andrew Gold, whose hit “Thank You for Being a Friend” became the theme of the NBC sitcom The Golden Girls, died in 2011.