SIR Paul McCartney remembered "the massively talented boy man with a gentle soul" as he paid tribute today to his occasional musical partner Michael Jackson.
The pair collaborated on tracks in the 1980s though the relationship was strained later by Jackson's ownership of much of the Beatles catalogue.
But Sir Paul spoke warmly of Jackson's talent and "gentle soul".
He said today: "It's so sad and shocking. I feel privileged to have hung out and worked with Michael. He was a massively talented boy man with a gentle soul. His music will be remembered forever and my memories of our time together will be happy ones.
"I send my deepest sympathy to his mother and the whole family and to his countless fans all around the world."
Sir Paul and Jackson initially teamed up to record the songs Say Say Say – later a single – and The Man, which were to be included on the former Beatle's Pipes Of Peace solo album. Jackson stayed with the McCartney family during the recordings.
Say Say Say, which they recorded at Abbey Road studios, was a US number one but stalled at number two in the UK.
The pair teamed up again later for the track The Girl Is Mine on the US star's Thriller release.
Released prior to the earlier songs, it is widely seen as the weakest on the album, and features the pair ribbing each other over their rivalry for the affections of "the girl". Jackson notably tells his collaborator: "Paul, I think I told you, I'm a lover not a fighter."
It was during their recordings that Sir Paul is said to have pointed out to Jackson how lucrative his back catalogue had been. And it was Jackson's purchase of that Northern Songs catalogue for 47 million dollars (28.5 million) – outbidding Sir Paul – in the mid-1980s which was to cause friction between them.
Despite Jackson's money problems over the past few years, his interest in the catalogue – and other publishing rights – has remained his biggest financial asset.
In the 1990s, Jackson merged his company with that of his label Sony's publishing wing and he has continued to hold a 50% stake in the Sony/ATV music catalogue. Jackson's interest is estimated to be worth in the region of 300 million.
There has been speculation that Jackson planned to eventually leave the rights to his one-time ally, but Sir Paul has claimed that some of the rights would revert to him in due course anyway.
In an interview in 2005, he said: "There are years approaching, there are dates approaching, that we never thought would approach, where things revert to me. So really, it's a waiting game rather than a big proactive buying game."