Jimmy Kimmel in tears talking about new son's troubled birth

US talk show host Jimmy Kimmel has opened up on the troubled delivery of his new baby, recounting the excruciating three-hour wait for his son to go through life-saving heart surgery moments after birth.

William Kimmel was born on April 21, 2017, and after several hours meeting his new family and resting with his mother, a nurse noticed that he had a heart murmur - and that he was starting to turn purple.

In a monologue on his show Jimmy Kimmel Live, he said young William was then rushed to the neo-natal ICU, and more and more medical staff started coming in to perform checks, bring in more equipment and provide him with oxygen.

He said they soon realised his son had a heart disease that had left a hole in his pulmonary valve.

"It was a terrifying thing," Kimmel explained through tears.

"My wife was back in the recovery room and had no idea what was going on, and I'm standing in the middle of a lot of very worried-looking people who were trying to figure out what the problem is."

He said they then rushed their child to the Los Angeles Children's Hospital, where a surgeon performed open heart surgery and fixed one of two defects as they waited. William will have to have another surgery in a few months, and a third in his early teens to fix the issue fully.

Jimmy Kimmel in tears talking about new son's troubled birth

Kimmel spent the next few minutes of his monologue thanking those at each hospital who had contributed to saving William's life, and recounting all the bizarre things that had gone on at the time.

"I'd just like to thank my wife Molly, first of all for letting me have sex with her in the first place - that was huge, so few have done that - but also for being so strong and level-headed and positive and loving during the worst nightmare a new mother could experience," he said.

"We had atheists praying for us. Even that son of a b*tch Matt Damon sent flowers," Kimmel said, referencing a faux feud he and the Hollywood actor have shared for many years.

The monologue was Kimmel's first appearance on the show since his son was born.