By Evan Henerson >Theater Writer

A shiny, new 50th-anniversary version of "My Fair Lady" has arrived in L.A. - and, appropriately, Marni Nixon with it. Except "the Voice of Hollywood" doesn't sing.

If you're detecting a certain irony in this, Nixon is, too.

After all, that's Nixon's voice you hear in the 1964 film version of "My Fair Lady" - and not Audrey Hepburn's - when Cockney flower girl Eliza Doolittle gushes "I Could Have Danced All Night."

But Nixon's still-resonant soprano is not on display as grand dame Mrs. Higgins in this "My Fair Lady" revival at the Ahmanson Theatre.

"It's sort of a joke," she says. "As long as people realize that I still do singing. Just not in this role. (Mrs. Higgins) doesn't have any songs."

Nixon, on the other hand, has plenty, though. During the Hollywood's golden age of movie musicals, she carved out a unique career as the singing voice for famed stars in musical roles.

Think Deborah Kerr "whistling a happy tune" in "The King and I" (1956), Natalie Wood feeling "oh so pretty" in "West Side Story" (1961) or Hepburn dreaming about a "loverly" life in "My Fair Lady." Nixon - uncredited at the time and under a studio contract demanding secrecy - provided the singing voices for all of them.

Nixon says she was happy to be part of the process.

"I was a concert singer and an opera singer, and so I was performing in front of the public a lot. It never occurred to me that I was just going to be a dubber. I think that's how I could do it so happily.

"I didn't take it as a put-down that I wasn't doing the role. It was just another aspect of working and keeping in the business and learning things," Nixon 78, adds. "Over the years, of course, it seems to have become a very important part of my life."

Her stage and vocal career have been anything but anonymous. In addition to her solo recordings "Marni Nixon Sings Gershwin" (a Grammy nominee) and "Marni Nixon Sings Classic Kern," Nixon appears on more than 30 albums and soundtracks, ranging from Stravinsky chamber works to providing the voice of Grandma Fa in Disney's "Mulan." And she frequently offers musical master classes.

It's hardly by accident that Nixon's autobiography is titled "I Could have Sung All Night."

"My Fair Lady," which played more than seven years and 2,700 performances on Broadway following its 1956 opening, is one of her favorites. In 1964, the same year she dubbed Hepburn's songs in the Oscar-winning film of "My Fair Lady," Nixon herself played Eliza on stage for New York City's City Center. It was the first of several times she would play the role.

"Everybody hopes they can get out of their station of life, and become somebody else," says Nixon. "So the play has a luminosity to it. You hope that, symbolically, if you work hard enough and apply yourself, you can get to the next rung on your own ladder."

And Mrs. Higgins?

"She's very much fun, very proper, and has a lot of humor and a lot of insight," Nixon says. "You have very few times to kind of establish that character, so you have to be right on top of it from the beginning. So that's fun."

This 50th-anniversary version of "My Fair Lady" originated at Britain's National Theatre under the direction of Trevor Nunn and featured choreography by Matthew Bourne.

Nixon, who hasn't been on the road since a short tour of "James Joyce's The Dead" in 2000, is looking forward to the L.A. stop, which gives her a chance to visit with children and grandchildren.

"I'll be able to do some master classes. It's like coming back home," says Nixon, who has lived in New York for the past 25 years. "I'm a native Californian, so it's like the chickens coming home to roost."

Evan Henerson (818) 713-3651

evan.henerson@dailynews.com

MY FAIR LADY

>Where: Ahmanson Theatre, 135 N. Grand Ave., L.A.

>When: 8 p.m. Tuesday through Friday, 2 and 8 p.m. Saturday, 1 and 6:30 p.m. Sunday; through April 27.

>Tickets: $30 to $100. (213) 628-2772, www.CenterTheatreGroup.org.