Kelly Osbourne is changing her son's last name after she and her boyfriend, Slipknot's Sid Wilson, had the biggest fight of their relationship about it.

On "The Osbournes Podcast," the "One Word" singer, 39, revealed that she and Wilson had a "huge" argument about naming their son, Sidney. She wanted the child, who was born in 2022, to have both of their last names, but Wilson "wouldn't let me," Osbourne said.

"I feel that I was forced into doing something I didn't want to do, and I can never, ever forgive him for that, but we can move on," Osbourne said.

She described this as the "biggest fight" that she and Wilson have "ever, ever, ever had, and probably ever, ever will," admitting that she never expected to talk about it publicly. The end result was that their son does not have a "double-barrelled last name," and Osbourne feels she had "literally no say" in this. But that will soon change, she revealed.

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"After lots of eye-opening conversations and some couples therapy, he has seen the light, and we are going to legally change our son's name to have both of our last names," Osbourne shared.

Osbourne argued that because "we both made our child," he "should have both of our last names," as one isn't "more important than the other." But Wilson didn't agree, Osbourne said, noting that he comes from a "really traditional English family."

She argued that he seemed more concerned with "pleasing his family" than pleasing her, even though "I'm his partner."

Osbourne confirmed she was pregnant with her first child in May 2022, writing on Instagram at the time, "I am over the moon to announce that I am going to be a Mumma. To say that I am happy does not quite cut it. I am ecstatic!"

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In a birthday post for her son in November, Osbourne said that she had the "most magical year of my life" because of him. "To watch you grow, learn and become a little man is the greatest joy I have ever felt," she wrote. "The most magical bond I have ever experienced is the bond I feel with you."

Osbourne added, "Before you love was just a word that I thought I understood. NOW I truly understand what love is. I am forever indebted to you for teaching me the beauty meaning and truth of love."