Sir Paul McCartney has added his tribute to late rocker Joe Cocker, revealing he'll forever be grateful to him for taking the Beatles' With A Little Help From My Friends to the top of the charts.

Cocker lost his battle with cancer on Monday (22Dec14), and stars including MCCartney's former bandmate Ringo Starr, Peter Frampton and Tom Morello were quick to pay their respects via Twitter.com.

The Yesterday singer added his tribute late on Monday, revealing he was thrilled with Cocker's cover of his song, which became the passionate rocker's signature tune.

MCCartney says, "It totally turned the song into a soul anthem and I was forever grateful to him for doing that."