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's official cause of death has come to light, days after the talent agent and ex-husband of Kelly Clarkson died of natural causes at age 48.

Less than 24 hours before the news of his death, Kelly Clarkson postponed her Vegas residency revealing that her children's father was 'ill'.

"Brandon Blackstock passed away peacefully at his home in Butte, Montana on August 7th under hospice care surrounded by his family,” Silver Bow County Coroner Dan Hollis tells PEOPLE, confirming that Blackstock's cause of death was melanoma; the manner of death was natural causes.

Blackstock has passed away following a secret three-year battle with cancer, a family spokesperson revealed in a statement.

Workhorse” Kelly Clarkson kept going during her ex Brandon Blackstock’s private three-year cancer battle because she had no other choice. The Grammy winner, 43, not only had a syndicated daily talk show to deliver,