Jimmy Kimmel tells of newborn son's brush with death and makes heartfelt plea for Obamacare

US TV host Jimmy Kimmel launched a heartbreaking plea for Obamacare after his baby nearly died.

He spoke of the "longest three hours of my life" as he told the studio audience of the ordeal he and his wife Molly went through during the surgery just days ago.

The Oscar's host said several hours after Molly gave birth on April 21 to William John, a "very attentive" nurse at the Cedars-Sinai Medical Centre in Los Angeles alerted the couple and doctors to the baby's slight purple colour and apparent heart murmur.

A sonogram showed his son was born with holes in the wall separating the right and left sides of the heart and a blocked pulmonary valve.

The baby, nicknamed Billy, was taken by ambulance to the Children's Hospital of Los Angeles to undergo surgery to open the valve.

He said there were concerns the baby's lack of oxygen was either due to a lung problem or heart disease, and there were fears it was the latter.

The Oscars host said of the moment he learned his son was ill: "It's a very terrifying thing."

The comedian then spoke passionately about healthcare in the US and criticised President Donald Trump's proposed cuts to the National Institutes of Health and praised Congress for instead calling for increased funding.

He said: "No parent should ever have to decide if they can afford to save their child's life."

President Trump has criticised Obamacare, calling it a "disaster" and has pledged to repeal the act.

Trump's attempt to replace it with a healthcare bill failed in March after he failed to win enough support for it to pass in Congress.

Kimmel said: "You know, before 2014, if you were born with congenital heart disease like my son was, there was a good chance you wouldn't be able to get health insurance because you had a pre-existing condition.

"If your parents didn't have medical insurance, you might not live long enough to even get denied."

He added: "If your baby is going to die and doesn't have to it shouldn't matter how much money you make.

"I mean I think that's something that whether you're a Republican or a Democrat or something else - we all agree on that, right?"

"This isn't football. There are no teams; we are the team. No parent should ever have to decide if they can afford to save their child's life. It just shouldn't happen, not here."