The 71-year-old rocker performed during a benefit concert for the singer by performing their hit, "Gimme Shelter" originally crooned by band's frontman Mick Jagger and Clayton, reported Hollywood Life.
Richards, who has been promoting his latest record, Crosseyed Heart, salute Clayton, 66, who recently had to undergo a double amputation after a serious 2014 car accident.
"Now you know how many friends you got, honey," Richards said.
The singer's epic backing vocals were well documented on the Oscar-winning documentary, Twenty Feet From Stardom.