Bruce Springsteen and Mick Jagger appear in the new film "Twenty Feet from Stardom," but only to shine the spotlight on the unsung backup singers who make them sound even better.
Opening in New York and Los Angeles on Friday and expanding across the United States in coming weeks, the music documentary features the lives and careers of singers who have harmonized with the likes of Ray Charles, The Rolling Stones, Elton John and many more.
The film features singers who sang on hit tracks beginning in the 1960s, like Merry Clayton and Darlene Love, right up to today, such as Judith Hill, a recent contestant on television singing show "The Voice."
Springsteen, Jagger and others talk about their work with the backup singers as their tracks play in the background, but the film focuses on the backup singers. The film shows them singing in a studio, whether harmonizing or taking the lead, and talking about their experiences.
American director Morgan Neville said he made the film because he became intrigued by their stories and found that even within the music community very little was known about them.
"It's not the last word, it's the first word," Neville said in an interview. "I didn't want it to feel like an anthology, I wanted it to feel like a narrative."
Most of the backup singers are African-American women who began singing in church at a young age. While some were content with supporting roles, others aspired to solo stardom.
"I always knew I wanted to be a singer, it was just, how we gonna do this?" said Clayton.
In the film, Clayton recounts being summoned at 2 a.m. to record with some unidentified English band in Los Angeles. She arrived at the studio in pajamas and hair curlers to learn that the band was the Rolling Stones and they were asking her to sing on "Gimme Shelter" - which became one of the band's signature titles and may be best-remembered today for her powerful vocals.
Despite her success as a backup singer for many stars ranging from Ray Charles to Neil Young to Lynyrd Skinner, on "Sweet Home Alabama," she never gained traction with a series of albums as an independent singer.
Other singers, such as Darlene Love, were thwarted by contract and management troubles. She resorted to cleaning houses to earn a living.
The film explores why each singer didn't make it solo, from their own perspectives and asking others in the industry. Among the reasons are simple bad luck, a lack of ambition or ego, and, perhaps, limited room at the very top for black female singers.
"Something that we kind of say in the film is that there were only so many slots for African-American singers at the time," Neville said about the 1970s.
Neville said that the landscape for backup singers has changed, but not necessarily for the better. With increased technology and current tastes tilting toward more electronic sounds there is less demand for backup singers.
Popular music, he added, also puts more emphasis on spectacle than on singing.
At 29, former "Voice" contestant Judith Hill is struggling to launch a solo career after singing backup for Elton John and Stevie Wonder. She said that the popular TV show has opened some doors for her and she is hopeful that she can achieve her dream.
"When you're a background singer, there's a springboard at the beginning, but it easily becomes quicksand if that's not what you want to do," she said.