Fatherhood has really changed Simon Cowell.

On Thursday, the “America’s Got Talent” judge appeared on “The Kelly Clarkson Show” and discussed his children’s book series Wishfits, co-written with his seven-year-old son Eric.

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“It’s been brilliant,” Cowell said. “I never thought I would do something like this.”

“I love that. That’s the juxtaposition of you doing this is so great for me. You’re like a different dude with a child,” Clarkson told him. “I think the vulnerable little side of you came out when you had a kid.”

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“Maybe,” Cowell responded. “After I lost my parents, I genuinely felt, Kelly, I would never feel that kind of love for anyone ever again. I thought that was it … until I saw the scan of him for the first time.

“From that moment I saw the scan, I was like ‘That is it, I’m besotted.’ Now I just cannot imagine my life without him. He’s the most amazing thing that ever happened to me. I adore him.”