Jimmy Kimmel's 7-year-old son has his third successful open-heart surgery

FILE - In this Aug. 22, 2016, file photo, ABC talk show host Jimmy Kimmel poses with then Democratic presidential nominee Hillary Clinton, unseen, during a break in taping of "Jimmy Kimmel Live!" in Los Angeles. Kimmel announced Wednesday, June 17, 2021, on his show that he will be the title sponsor of college football's LA Bowl that is scheduled to be played Dec. 18 at SoFi Stadium in Inglewood, Ca. (AP Photo/Carolyn Kaster, File)
Jimmy Kimmel, whose son was born with serious heart defects, has used his platform to advocate for affordable healthcare in the United States. (Carolyn Kaster / Associated Press)

Jimmy Kimmel's 7-year-old son is recovering from open heart surgery — again.

"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 late-night host posted Monday on Instagram alongside a photo of the boy smiling in his hospital bed, wearing a gown covered in cartoon tigers.

Read more: Bret Baier's teenage son Paul is in recovery after emergency open-heart surgery

The post inspired an outpouring of support from celebrities, who took to Kimmel's social media to share their well-wishes.

"Sending love to your whole family and a thanks to everyone at CHLA for everything you do," Ellen DeGeneres commented.

"We love you so much Billy! You’re a little warrior," Olivia Munn added.

"God bless your little Billy," John Stamos wrote. "He’s lucky he has parents like you and also the care of the good folks at CHLA."

Other star supporters included Jennifer Aniston, Carson Daly, Andy Cohen, Michelle Pfeiffer, Jenna Dewan and Justin Theroux.

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Kimmel expressed his gratitude for the continuing support from Hollywood, the public and his family.

"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 for being stronger than is reasonable for any Mom to be and Billy, you are the toughest (and funniest) 7 year-old we know," he wrote.

Billy was born with a condition called tetralogy of Fallot with pulmonary atresia, a severe heart defect that occurs in approximately one in 2,500 babies. The condition affects the ability of blood to flow through the heart and bring oxygen to the body and requires immediate medical intervention.

Kimmel's disclosure of his son's condition in a tearful monologue on "Jimmy Kimmel Live!" went viral in 2017, as the host recounted the "longest three hours" of his life while his 3-day-old child underwent open heart surgery, and he thanked every healthcare worker who treated his son by name.

Read more: After his son is born with heart condition, Jimmy Kimmel calls for healthcare bickering to end

Kimmel had already been a supporter of Children's Hospital Los Angeles, where Billy has been treated, but the experience made the late-night host a fierce advocate for affordable healthcare.

"No parent should ever have to decide if they can afford to save their child's life," Kimmel said in his monologue. "It just shouldn't happen. Not here."

Kimmel continued to voice his support for CHLA and affordable healthcare in his recent post.

"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 wrote.

"There are so many parents and children who aren’t fortunate enough to go home after five days. Nothing matters more than taking care of each other."

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This story originally appeared in Los Angeles Times.