As Jimmy Kimmel‘s youngest son Billy turns 5, the talk show host and his wife, Molly McNearney, are thanking doctors for “saving his life.”

On Instagram, Kimmel thanked doctors at Los Angeles’ Cedars Sinai hospital for performing a pair of heart surgeries on his boy, to correct a heart condition with which Billy was born.

“Happy 5th birthday to our little nut,” Kimmel captioned a picture of Billy smiling as he sits behind his birthday cake. “We are eternally grateful to the brilliant doctors and nurses at @ChildrensLA & @CedarsSinai for saving Billy’s life.

Kimmel added, “And to those of you whose donations, prayers and positive thoughts meant everything. Please support families who need medical care.”

Billy underwent his first open-heart surgery at just three days old, and had another when he was seven 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 Kimmel to become an advocate for health care.

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