Amy Winehouse's father has revealed his tragic daughter was winning her battle with drugs and alcohol at the time of her death in July (11).

Mitch Winehouse insisted the Rehab singer did not die of a drug overdose, as was widely reported after her body was found at her north London home - and his comments were validated by the a toxicology report, released last month (Aug11), which showed the star was not taking illegal drugs at the time of her death.

Now, Amy's father has opened up further about the tragedy, telling newsman Anderson Cooper his daughter died after suffering a seizure caused by alcohol detoxification.

In a preview of Cooper's interview with Mitch and Janis Winehouse, Amy's mother, which will air on Monday (12Sep11), the singer's father reveals officials only found the prescription drug Lithium in his daughter's system - and she was taking that to fight the symptoms of alcoholism.

Mitch says, "Everything Amy did, she did to excess. She drank to excess and did detox to excess."

But he is convinced the star was well on her way to recovering from years of drug and alcohol abuse, adding, "The periods of abstinence were becoming longer, and the periods of drinking were becoming shorter. It was headed in the right direction."

A full inquest into the singer’s death will begin next month (Oct11), according to Mitch Winehouse.