Paul McCartney and Michael Jackson worked alongside each other on numerous occasions, noteably on song 'Say Say Say', released in 1983.
But the Beatles legend has revealed that he had no idea about MJ's dark side before watching his latest documentary 'Leaving Neverland'.
"I think it’s sad,” McCartney told Radio Futuro in Chile, where he has been performing.
"Obviously Michael was a great singer, a great artist and a great dancer. For years we’ve loved that. Nobody knew about the other side that’s shown in that movie. When I knew him he was a really nice guy. I didn’t know about the dark side. It makes it very difficult to look back on the memories which were good memories, to think, oh boy, there was other stuff going on."
"For me, I’m OK to just stay with the personal memories I had of him. The other side is the other side. I don’t know about that. I can understand why people are very disappointed in him and angry that he had the dark side."