Jimmy Kimmel's wife Molly McNearney ''couldn't believe the strength it took'' the star to speak about his son's life-threatening condition.

The 50-year-old talk show host revealed on his show 'Jimmy Kimmel Live!' earlier this year that his seven-month-old son Billy had been born with a congenital heart defect, and had to undergo open-heart surgery when he was just three days old.

Jimmy made the speech during his show to advocate for affordable health care, and his wife Molly - who is the co-head writer on the programme - ''sobbed through the entire thing'', because she was stunned by his selfless words.

She said: ''I didn't think much of it. I figured he'd tell the story and then he'd probably cry because, well, he once cried on the show over a lion dying.

''That Monday, Billy was finally home, and Jimmy was back at work. Even though I was on maternity leave, I was still getting all of my work emails, and I didn't get one with the monologue for that night. I emailed Jimmy, and he said, 'I just want you to watch.'

''So, there I am, in my living room breastfeeding Billy with my mom beside me, and we're watching. I sobbed through the entire thing. I couldn't believe the strength that it took to tell that story a week after it happened. He didn't have to do that. Our family has excellent health care; he had nothing to gain from that. He did it for the other people whom we met in that hospital. He came home that night, and I just hugged him and I wouldn't let go.''

The blonde beauty - who also has three-year-old Jane with the show host - admits that she isn't fond of the world knowing about her son's health condition, but insists the reminder that they're ''helping other people'' by speaking out has far outweighed her ''fears''.

Speaking to The Hollywood Reporter magazine, she said: ''I don't necessarily like that everyone knows what's going on with the health of my child. And it's scary to make yourself vulnerable the way we have, but the encouragement that we're helping other people far outweighs my fears about our lack of privacy.

''I'm looking forward to the day that I get to tell him about all of this. I want to be the one to tell Billy what his dad did for him.''