One of the great unsung stars of Hollywood was Marni Nixon, a voice double whose singing stood in for such actresses as Deborah Kerr in "The King and I," Natalie Wood in "West Side Story," and Audrey Hepburn in "My Fair Lady." Nixon, who passed away this week at age 86, was interviewed by Charles Osgood for a story originally aired on "Sunday Morning" on [insert full date].