The eccentric singer claims she always felt like a "freak" because her school's strict rules forbade cosmetics, so she used to indulge in her desire to dress up before going to sleep.
She explained to WWD: "When I was young, I felt like a freak in school - and I had to put my make up on when I got home before I went to bed because I wasn't allowed to wear make-up in school.
"When I walked around the corner and saw Boy George in the window of a MAC store, I said, 'I feel just like that!' Why is that attitude nowhere else? And RuPaul, and Pamela Anderson.…I said, 'Gosh, I feel just like that.'
"That's why I think MAC is so important; they cater to that inside of you that feels like a freak sometimes, that wants to raise your freak flag."
The 'Paparazzi' star – who is fronting a new campaign for the MAC Aids Fund – has also claimed she used to be incredibly insecure and has only learned to have confidence in herself through the support of her fans.
She told the 'Today' show: "I was so insecure for so long and my fans have believed in me so much that I have become this confident woman I want to bring back to them.
"I try in my own way to be a spokesperson and say, 'Its OK if you don't feel like a winner, or you're a loser'. I wanted to win at the Grammys for my fans because you want to be everything they imagine you to be. "