Marni Nixon dead: Natalie Wood, Audrey Hepburn voice dies at 86

Marni Nixon, a singer whose voice appeared in Hollywood films like The King and I and My Fair Lady, has died of breast cancer, the New York Times confirmed. She was 86.

Nixon began dubbing for leading actresses in the 1940s, and most notably sang Deborah Kerr’s parts in both 1956’s The King and I and 1957’s An Affair to Remember, along with Natalie Wood’s parts in 1961’s West Side Story and Audrey Hepburn’s songs in 1964’s My Fair Lady — but there was a time when no one knew that the singing voice was hers.

“It was all very secretive when I did the dubbing for The King and I and West Side Story,” she told PEOPLE in 2015, “but everybody in the industry knew it was happening. The orchestra members don’t know you were supposed to keep it secret. But it gradually got around.”

Because of her uncredited work, TIME called Nixon “the ghostess with the mostest” in a 1964 article. “It gets harder and harder to adapt yourself to the person you’re dubbing,” she told the magazine at the time. “Eventually you want to play the character yourself.”

She elaborated on the cons of staying behind the camera in a 1967 interview with the Times, where she said “the anonymity didn’t bother” her until West Side Story. “Then I saw how important my singing was to the picture,” she said. “I was giving my talent, and somebody else was taking the credit.”

She eventually did get to take the spotlight as a concert singer for the New York Philharmonic, along with other orchestras, and more recently appeared in Broadway shows like 2000’s James Joyce’s the Dead and 2001’s Follies. These performances marked her first time on Broadway since taking the stage in 1954’s The Girl in Pink Tights.

In 2006, she released a memoir titled I Could Have Sung All Night: My Story, written with Stephen Cole. In 2008, she received the Distinguished Artist Award from New York’s Singer Symposium.