Jimmy Kimmel Reveals Son Billy, 7, Had Third Open-Heart Surgery Over Memorial Day Weekend: 'We Went Into This Experience With a Lot of Optimism and Nearly as Much Fear'

Jimmy Kimmel has revealed that his youngest son Billy, 7, had his third open-heart surgery at Children's Hospital Los Angeles (CHLA) over Memorial Day weekend, RadarOnline.com has learned.

"This weekend, our boy Billy had his third (of three, we hope) open-heart surgery," Kimmel captioned a photo of his son smiling from his hospital bed.

"We went into this experience with a lot of optimism and nearly as much fear and came out with a new valve inside a happy, healthy kid," he added in the Instagram post.

The comedian went on to thank "Billy’s doctors, led by the brilliant surgeon Vaughn Starnes, cardiologist Tim Casarez and the excellent, hard-working staff, doctors, nurses and nurse practitioners at CHLA, including, but certainly not limited to Misty, Ann, Sylvia, Dana, Caleigh, Nick, Bekah, Julie, Kenny, Caroline, Lisa, Stephanie, Ellize, Ivy, Pam and Carrie" who "came through for us with immeasurable kindness and expertise."

"Walking around this hospital, meeting parents at their most vulnerable, children in pain and the miracle workers who do everything in their considerable power to save them is a humbling experience," he wrote. "We hope you never need CHLA, but if you do - know that they help families regardless of their ability to pay, thanks largely to the Affordable Care Act (another salute to the late Senator John McCain), generous donations from companies like Disney, which I am proud to work for and especially from generous people like you."

"Thanks to those loving strangers who took time to pray for and send positive energy to our baby, thanks to our family and friends for rallying around us to an almost-ridiculous extent, thank you to my wife Molly [McNeary] for being stronger than is reasonable for any Mom to be and Billy, you are the toughest (and funniest) 7 year-old we know. There are so many parents and children who aren’t fortunate enough to go home after five days. Please share your love, hearts and prayers with them."

Kimmel first revealed Billy's congenital heart condition in an emotional speech on his Jimmy Kimmel Live! late-night show shortly after his son's birth in 2017.

"They did an echocardiogram, which is a sonogram of the heart, and found that Billy was born with a heart disease," Kimmel explained. "Something called tetralogy of Fallot with pulmonary atresia. Basically, the pulmonary valve was completely blocked, and he has a hole in the wall between the left and right sides of his heart."

Billy underwent his first successful open-heart surgery at just three days old and had a second several months later to close the holes. "They want to have a third, hopefully non-invasive procedure sometime maybe in his early teens to replace the valve he has now," Kimmel said in 2017.

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Since Billy's birth, Kimmel has become a staunch supporter of CHLA and an outspoken advocate for healthcare reform.

Kimmel and his wife Molly McNeary, an executive producer and co-head writer on his show Jimmy Kimmel Live!, also share a 9-year-old daughter Jane.

In addition, Kimmel has two adult children, Katie, 32, and Kevin, 32, from his first marriage to Gina Maddy from 1988 to 2003.