One of the demons Amy Winehouse struggled with before her death last year was jealousy over the success of Adele, according to Winehouse's former producer, Mark Ronson, who had first-hand knowledge of the singer's mental state in the months before her passing.

Ronson told the Village Voice he had been hoping to work with the 'Rehab' singer again before she died. He explained that he met with Winehouse to discuss the project but found she was not in a good place:

But, what little time we had, well, it was tense. She was in a bad state, God knows why. I think that the Adele thing had Amy freaked out. She liked her, but Adele's success was making Amy feel upset, competitive, restless. Anyway, we lost touch briefly. And before she and I could really start the process of beginning a new album, it was too late.

Lots of performers have competitive streaks, but it would be a shame if Adele's success in any way caused Winehouse mental anguish. Adele's '21' album had started to explode thanks to the singles 'Rolling in the Deep' and 'Someone Like You' when Winehouse died last July of alcohol poisoning.

Ronson produced most of Winehouse's 'Back to Black,' which won the singer five Grammy Awards and sold more than 10 million copies around the world. He co-wrote the title track and produced most of Winehouse's well-known songs, including 'Rehab,' 'You Know That I'm No Good,' 'Love is a Losing Game' and 'Valerie.'

Watch Mark Ronson's 'Valerie' Video Feat. Amy Winehouse Vocals