One week after Jimmy Kimmel revealed that his son, Billy, had been born with a heart defect, the comedian returned to host his late night show with an emotional update on his son's health and a defense of his foray into the country's heated debate on health care.

The "Jimmy Kimmel Live!" host also thanked his fans for their "humbling outpouring of support" and said that he and his wife were "very grateful" for the multitude of donations made to the Children's Hospital of Los Angeles, where his son was treated.

"First I want to tell you because so many people have asked: Our son Billy is doing very well," Kimmel said. "He's eating. He is getting bigger. He is sleeping well. He can read now -- which they say is unusual [for a child his age]."

Kimmel, 49, revealed last Monday that his son underwent surgery on his heart three days after he was born, and will require another procedure when he's a little bigger in three to six months. During his monologue, Kimmel asked all politicians to come together to ensure healthcare for all Americans, especially those who have pre-existing health conditions. Though there were many who supported Kimmel's point of view, he noted that there were many others who called him an "out of touch Hollywood elitist." To those critics, the late night host offered a sarcastic apology.

"I'd like to apologize for saying that children in America should have health care," he joked. "It was insensitive – it was offensive – and I hope you can find it in your heart to forgive me."

To further the conversation, he interviewed Bill Cassidy, a Republican senator from Louisiana who last week tweeted that there should be a "Kimmel Test" for any healthcare bill passed.

Children's Hospital LA received 'several hundred calls' after Jimmy Kimmel plea

Jimmy Kimmel reveals newborn son's heart defect in emotional monologue

The Jimmy Kimmel Test, he noted, would be in place to ensure that any healthcare plan would adequately cover pre-existing conditions "but in a fiscally conservative way that lowers cost."

"I happen to like [it] a lot," Kimmel said. "He is a doctor – a gastroenterologist. He is married to a retired doctor -- his wife Laura, was a surgeon. And he co-founded the Greater Baton Rouge Community Clinic, which provides free dental care and health care to the working uninsured. So obviously – this is someone who cares about people's health."

Others on-hand for Kimmel's first night back are Zach Galifianakis, Tracee Ellis Ross, and the band Logic.