Jimmy Kimmel's son is "doing great" after undergoing heart surgery.

The 54-year-old talk show host is father to Katie, 31, Kevin, 29, Jane, eight, and five-year-old William from various relationships and joked that his youngest is a "little screwy" but is doing well as he prepares to undergo a third round of open heart surgery.

He said: "Billy's doing great. He's perfectly normal - I shouldn't say he's normal, he's not a normal kid, he's a weird kid, but his heart is fine. He's a little screwy, that's all we're worried about right now. He's doing great. He still has to have another surgery."

The 'Jimmy Kimmel, Live!' star went on to explain that people are sometimes "hesitant" when it comes to asking about the health of his son and insisted that William is "perfectly fine" as he heaped praise upon the hospital staff.

He told ETOnline: "The Children's Hospital here in Los Angeles - it's just a great place for parents to bring their kids when it's needed, but also it's a great place because they train doctors and nurses from not just all around the country, they go all around the world. It's a place where they come, they learn how to do this, and it helps everybody across the whole country, not just L.A. People - I think they're very hesitant to ask me about him, and they're like 'Is he okay?' And he's honestly no different physically than any of the other kids. He can play sports - he doesn't want to, but he can. He's always dancing and jumping around, and we wrestle all the time.

"There's some bad things about being famous, and there are some good things about being famous, and one of the best things about it, is that you and shine a light on these people who really are the stars. When you can do something for somebody's kid, they become the most important people in the world, and to me, these people are."