Linda Lewis provided backing vocals on Bowie's Aladdin Sane album but my favourite clip of her is providing backing vocals for Terry Reid at the first Glastonbury Festival.
She makes her entrance at 6.29 just after the naked bouncing breasts on the girl on the motorcyle.
This is a brilliant...
David Crosby on Phil Collins "Another Day in Paradise" and also with Graham Nash on Jackson Browne's "Doctor My Eyes"
https://youtu.be/Qt2mbGP6vFI
https://youtu.be/qsM7qCulsRM
Emmylou Harris has sung on various other artists records including Gram Parsons, Bob Dylan, Neil Young, Elvis Costello, Warren Zevon, Little Feat, Linda Ronstadt, Lyle Lovett, Johnny Cash, Ladysmith Black Mambazo amongst others.