Jimmy Kimmel's 7-Year-Old Son Billy Has 3rd Open Heart Surgery

The Jimmy Kimmel Live! host took to Instagram Monday to share a picture of his and Molly McNearney's son smiling in a hospital room, as he revealed that the 7-year-old had undergone his third open heart surgery.

"This weekend, our boy Billy had his third (of three, we hope) open heart surgery. 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," the TV personality wrote.

Kimmel continued his message by thanking Billy's surgeon and the medical professionals at Children's Hospital Los Angels who were there from the operation to recovery. The late-night host also gave a special shoutout to the parents he met while in the hospital.

"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," he continued.

The comedian went on to thank his family, friends and wife -- for being so strong.

"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," he wrote. "Thank you to my wife Molly for being stronger than is reasonable for any Mom to be."

Kimmel ended the post with a sweet message to his son, who he called the "toughest" and "strongest" kid he knows.

"And Billy, you are the toughest (and funniest) 7 year-old we know," Kimmel wrote. "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 and if it moves you, support @ChildrensLA (link in bio) or a great children's hospital near you (@CMNHospitals). Nothing matters more than taking care of each other. With love and gratitude, Jimmy."

The post was met with lots of love from Kimmel's fans, friends and celebs alike -- many of whom took to the comments, including John Stamos, who wrote, "God bless your little Billy. He’s lucky he has parents like you and also the care of the good folks at CHLA."

Bravo exec, Andy Cohen, also commented, writing, "Love to Billy!!!❤️," with fellow TV personality, Carson Daly, writing, "We love you Billy."

Kimmel first opened up about Billy's health struggles in 2017, in a now-viral, tearful monologue on his late night show, in which he revealed that his youngest son had been born with a heart defect and underwent open-heart surgery at three days old.

In the years since, Kimmel, who also shares daughter Jane, 9, with McNearney, has marked Billy's birthday by sharing his gratitude to all those involved in his son's medical care.

In April, Kimmel celebrated Billy's 7th birthday with a sweet note and update on his health.

"Billy turns 7 today and is doing great thanks to the doctors, nurses, therapists and staff at @ChildrensLA & @CedarsSinai," he captioned a series of photos featuring his son. "Billy is asking friends 'to give $7 because I'm seven to help kids in the hospital.' (he also wants a spy kit) His goal is 'to raise $100 to help sick kids.' If you’d like to donate - thank you and link in bio."

Kimmel, who is also dad to Katie, 32, and Kevin, 30, from marriage to ex-wife, Gina Maddy, followed up his post with an update and more sweet photos of Billy.

"This boy is seven years old because of you," he wrote next to a close up shot of Billy smiling. "Molly and I are overwhelmed by your generous donations to @childrensla and kind messages. Thank you for all the love. We wish you and your families good health and great friends."

Billy's Children's Hospital Los Angeles fundraising site had raised more than $42,000.