Thriller producer Quincy Jones says that his pal Michael Jackson bleached his skin because he "didn't want to be black".

The singer always claimed that his increasingly pale appearance was the result of Vitiligo, a chronic condition that causes patches of skin to lose pigment.

However, Quincy – who also worked with Michael on Off The Wall and Bad – dismisses this explanation as “bulls**t”.

He says in a candid new interview: "I don't believe in any of that bulls**t, no. No. Never.

"I've been around junkies and stuff all my life. I've heard every excuse. It's like smokers - 'I only smoke when I drink' and all that stuff. But it's bulls**t.

"You're justifying something that's destructive to your existence. But when somebody's hell-bent on it, you can't stop 'em.

"What his face turned into is ridiculous. Chemical peels and all of it. And I don't understand it. But he obviously didn't want to be black. You see his kids?"

Quincy (second left) in the studio with Michael (far right), Smokey Robinson (far left) and Lionel Richie (second right) while recording charity single 'We Are The World'  in 1985

Quincy suggests Michael was a hypochondriac, but is unable to explain why his friend had such a problem with the way he looked.

"He'd come up with, 'Man, I promise you I have this disease,' and so forth, and 'I have a blister on my lungs,' and all that kind of bulls**t," he tells Details.

"It's hard, because Michael's a Virgo, man - he's very set in his ways. You can't talk him out of it.

"I'm just a musician and a record producer. I'm not a psychiatrist. I don't understand all that stuff. We all got problems."

Black to white: Michael's changing appearance

After learning of his friend's death, Quincy praised Michael for his "talent, grace, professionalism and dedication" in an emotional tribute.

RIP Michael Jackson 1958 - 2009