More details of the death of Brandon Blackstock , the talent manager and former husband of Kelly Clarkson , have come to light ahead of his Aug. 17 memorial service.

A death certificate , officially filed Thursday in Butte, Montana, confirmed the 48-year-old died of natural causes related to malignant melanoma , an aggressive form of skin cancer.

But the father of four, who battled cancer for three years , also suffered from seizures. They were listed as “significant conditions contributing to death but not resulting in the underlying cause,” according to the documents obtained by TMZ and People.

Blackstock died on Aug. 7 at his home in Butte while under hospice care, according to the Silver Bow County coroner, who initially confirmed the details of his cancer to People.

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