Amy Winehouse released 'Rehab' as a "cry for help"

He told E! News: "I don't think she liked the song. It's dark and it's a cry for help. I think she was surprised it became a hit. The trouble was already there, but that's when it really kicked off.

"That song becomes, I think, the thing that she hated. People wanted her to sing it and she's singing it with a drink in her hand. It's a cry for help. Every time she's says, 'No,' she's saying, 'Yes.'"

The documentary - which premiered at the Cannes Film Festival - has been criticised by some of Amy's closest family and friends.

In a previous statement, a spokesperson for Amy's immediate family said: "The Winehouse family would like to disassociate themselves from the forthcoming film about their much missed and beloved Amy ...

"They feel that the film is a missed opportunity to celebrate her life and talent and that it is both misleading and contains some basic untruths. There are specific allegations made against family and management that are unfounded and unbalanced."

Whilst Amy's goddaughter Dionne Bromfield said of the biopic: "No film is ever going to be able to tell me about the Amy I knew."