United Kingdom, Aug. 8 -- Kelly Clarkson is "staying strong" for her kids following Brandon Blackstock's passing.

The talent manager died on Thursday (07.08.25), aged 48, after battling cancer for more than three years, and Kelly is feeling "heartbroken" for their two children.

A source told People: "Kelly and Brandon had their ups and downs, but at the end of the day, he was the father of her children and she is absolutely heartbroken for them. Her kids are her entire world, and she's staying strong for their sake."

Brandon - who had River, 11, and Remington, nine, with Kelly - served as the pop star's manager during their marriage. And despite their acrimonious break-up, Kelly always tried to remain "classy" for the sake of their kid...