Jimmy Kimmel's son Billy turned 7 on Sunday, and the talk show host is thanking the medical staff at two well-known Los Angeles hospitals for the milestone.

He and Billy are also paying it forward by raising money for some of the children there.

"Billy turns 7 today and is doing great thanks to the doctors, nurses, therapists and staff at @ChildrensLA & @CedarsSinai," explained Jimmy, whose son needed surgery to correct a congenital heart defect.

"Billy is asking friends 'to give $7 because I'm seven to help kids in the hospital,'" he continued, adding of his son, "He also wants a spy kit."

Kimmel explained Billy's goal is "to raise $100 to help sick kids" and invited others to kick in.

Billy underwent his first open-heart surgery at just 3 days old and had another when he was 7 months old. His health took center stage after he was born in 2017, when Kimmel shared with his audience the trials the newborn was facing. "Poor kid. Not only did he get a bad heart, he got my face," he said at the time.

Kimmel tearfully told viewers of Billy's successful but "terrifying" first surgery, calling it "the longest three hours of my life." At the time, Kimmel individually named the "awe-inspiring" doctors and nurses who saved Billy and countless others.

His son's health struggles led him to become an advocate for health care.

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