A California labour commissioner has ruled that Blackstock, 46, must pay $2,641,374 to his ex-wife, after he unlawfully procured deals that should've been handled by a talent agent.
The ruling - which has been obtained by PEOPLE - reads: "Under the Talent Agencies Act (TAA), a manager, like any person without a talent agency license, cannot procure or attempt to procure employment for artists."
In a lawsuit filed against her ex-husband, the 41-year-old pop star claimed that he secured her contracts with 'The Voice', 'The Kelly Clarkson Show', Norwegian Cruise Line, Wayfair and the Billboard Music Awards, and then took the fees himself.
Blackstock’s legal team has already filed to appeal the ruling.
Meanwhile, Clarkson previously revealed that her kids continue to "dream" that she'll reunite with her ex-husband.
The singer - who was married to Blackstock between 2013 and 2021 - admitted that her children continue to hope for a reconciliation.
Clarkson - who has River, nine, and Remington, seven, with her ex-husband - told the 'We Can Do Hard Things' podcast: "Your kids will still have a hard time. It doesn't matter if you stay, it doesn't matter if you go, I am still having conversations [with my kids] three years later.
"My kids just came back from my ex and any time there's mention of maybe him being with somebody else ... they are just really adamant about keeping that dream alive that we might still be together one day."
Despite this, Clarkson believes she's actually become a better mom since their split.
She said: "I'm a far better mother because when you're honest with yourself, you're able to be honest with others."