In a new interview with Details, Quincy Jones -- who helped launched Michael Jackson's career -- opens up about the sad and strange evolution in the late singer's appearance over the years.

Jones - who first worked with Jackson on 1979's Off the Wall - tells Details they'd talk "all the time" about how Jackson was changing.

"But 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 b.s.," he says. "It's hard, because Michael's a Virgo, man -- he's very set in his ways. You can't talk him out of it. Chemical peels and all that stuff."

See how Michael Jackson's face has changed over the years

"I've been around junkies and stuff all my life. I've heard every excuse," he says. "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. It's crazy."

Revisit Michael Jackson's most unforgettable moments

Jones says Jackson's obsession with his appearances got to be "ridiculous."

"Chemical peels and all of it. And I don't understand it," he says. "But he obviously didn't want to be black." Asked if that is the reason Jackson had undergone so much plastic surgery, Jones says, "Well, what do you think? You see his kids?"

See photos of Michael Jackson and his kids through the years

Jones isn't sure why Jackson had such a deep-seated issue with the way he looked. (In a 1993 interview with Oprah Winfrey, The King of Pop said he used to wash his face in the dark because he had pimples. "I wouldn't want to look in the mirror... and my father teased me," Jackson said. "He would tell me I was ugly.")

"I'm just a musician and a record producer. I'm not a psychiatrist," Jones says. "I don't understand all that stuff. We all got problems. But there's a great book out called Too Soon Old, Too Late Smart. Did you see that? That book says the statute of limitations has expired on all childhood traumas. Get your stuff together and get on with your life, man. Stop whinin' about what's wrong, because everybody's had a rough time, in one way or another."

Look back at Michael Jackson's life

So what does he think killed Jackson (who died June 25 at age 50 after suffering cardiac arrest)?

"I would think that the pressure of the concerts and the debt and everything else..." he says. "...If you sit there and just stay hung up on one negative thought, you will become that thought. I know that Lisa Marie Presley said that she always thought he was going to die like Elvis. You sit and think about that stuff, it'll happen to you. If you start thinking about darkness instead of light, or fear instead of love, you'll get in trouble. I really believe that."

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