Talent manager Brandon Blackstock had "bravely battled cancer for more than three years" when he died at 48 years old.
His health condition was shared in a statement from the Blackstock family, obtained by USA TODAY on Aug. 7.
"It is with great sadness that we share the news that Brandon Blackstock has passed away. Brandon bravely battled cancer for more than three years. He passed away peacefully and was surrounded by family," the statement read.
Blackstock and Kelly Clarkson, who were married for seven years until their June 2020 divorce, share two children: River Rose Blackstock, 11, and Remington "Remy" Alexander Blackstock, 9. He also has two children from his previous marriage to Melissa Ashworth: Savannah and Seth Blackstock.
In the evening of Aug. 6, a day before Blackstock's family shared the news of his death, Clarkson announced the upcoming dates of her Las Vegas residency would be postponed because "this past year, my children's father has been ill and at this moment, I need to be fully present for them."
