The Crazy Little Party Girl hit-maker spent a month in rehab earlier this year, "emotional and spiritual" issues with the King of Pop had been friends.
The 23-year-old told OK! Magazine. "I never talked about it ... This is the first time. I do ... I miss Michael ... I have spent such incredible times with him. I did things with him that nobody else did ... But I was also troubled about what he did to me. Yes, he gave me wine. I mean, I could have refused, but I was 15".
He added, "He gave me cocaine. I felt weird about that and other stuff ... We spoke afterwards, hours and hours, on the phone. I admired Michael, but his behaviour bothered me a lot. Then my mother called the police".