Grammy nominated music video director Morgan Neville collected this year's Oscar for Best Documentary Feature for this rousing, feel-good portrait of some of the unknown voices behind music's most recognisable hits.

Twenty Feet From Stardom celebrates the invaluable contributions of backing singers to the music industry and introduces us to a few of the talented women, whose tireless work in music studios and at concert venues is often taken for granted by the fans.

It's a rich, detailed and inspiring valentine to those people behind the scenes who deserve so much credit, but rarely get it: like singer Merry Clayton, who sings a key phrase in the chorus of the Rolling Stones' Gimme Shelter.

Neville reminisces with her about her time with Mick Jagger and the band and in one of the film's many hilarious moments, the director asks her to turn down her car radio because it is impacting on his sound recording. "How can you logically have a diva not have her music on?" she responds sassily.

Divas abound of every age and background, from seventy-something trailblazer Darlene Love, who worked with The Beach Boys, Tom Jones, Elvis Presley and Dionne Warwick, to relative newcomer Judith Hill, who was rejected during the live finals of the 2013 series of The Voice in America.

Neville intercuts interviews and behind-the-scenes footage of the backing singers with anecdotes and tributes from luminaries including Sheryl Crow, Bette Midler, Bruce Springsteen, Sting and Stevie Wonder.

Twenty Feet From Stardom appeals to our basic human desire to champion the underdog, reminding us that behind every recording artist is a panoply of brilliant people, whose contributions are reduced to credits on an album sleeve.

The backing singers are brilliant performers in their own right, not least R&B vocalist and songwriter Lisa Fischer, who won a Grammy in 1992. Her vocal virtuosity is truly dazzling - it's little wonder she has accompanied the Rolling Stones on tour since 1989. Jagger knows a good thing when he hears it.