The official cause of death for Kelly Clarkson's ex-husband, Brandon Blackstock, has been confirmed. Silver Bow County Coroner Dan Hollis told Us Weekly on Monday, August 11, that Blackstock's cause of death was melanoma, a form of skin cancer, and the manner of his death was natural causes. "Brandon Blackstock passed away peacefully at his home in Butte, Montana on August 7th under hospice care surrounded by his family," Hollis said in a statement. Blackstock died on August 7 after privately battling cancer for three years. He was 48.