Speaking to the Sunday Times, he explained: "I was doing a film with Roman Polanksi, The Ninth Gate, and across the room I saw this woman's back.
"I saw this neck attached to the back, and I was sort of fascinated by it. Honestly, it was a very beautiful sculptural thing. Then suddenly the back and the neck turned, and it had a face."
The pair had met several years before, and Depp revealed that the French singer asked him: "Hi, do you remember me?"
He added: "'I knew it was over - I was done. I was in big trouble from that second on."
Depp's latest movie The Tourist was released in cinemas earlier this month.
