Brandon Blackstock, ex-husband of music star Kelly Clarkson, died last Thursday, August 7. An official cause of death for the 48-year-old has been confirmed. Silver Bow County Coroner Dan Hollis told PEOPLE Monday that Blackstock died of melanoma,

Brandon Blackstock, who was a manager and Kelly Clarkson's ex-husband, died at the age of 48. That came a day after Clarkson publicly revealed that she postponed her residency in Las Vegas, which she did because -- as she said "my children's father has been ill and at this moment, I need to be fully present for them."

Brandon Blackstock, the talent manager and former husband of Kelly Clarkson, died of melanoma, a form of skin cancer, on Aug. 7. The Silver Bow County Coroner Dan Hollis tells PEOPLE Blackstock "passed away peacefully at his home in Butte,