Jimmy Kimmel has thanked fans for their ''love and support'' after he opened up about his son's heart operation.

The 48-year-old American television presenter announced his wife, Molly McNearney, gave birth to their child William on April 21, but the tiny tot had to undergo an invasive procedure within a matter of hours after he was born because he had ''two defects in his heart'', which left the parents fearing the worse.

After opening up about the ordeal during his monologue on Monday's (05.01.17) episode of 'Jimmy Kimmel Live', the show's host - who also has daughters Katie, 25, and Jane, two, as well as 23-year-old son Kevin - took to Twitter to thank his fans for their kind words of support.

Posting a picture of his wife with their son - who is nicknamed Billy - and Jane, the star wrote: ''sincere thanks for the outpouring of love & support - Dr. Jane is keeping a close ear on Billy, who is very well - XO (sic)''

Speaking on the show on Monday, Jimmy said his son's operation marked the ''longest three hours'' of his life.

He said: ''On Monday morning, Dr. Vaughn Starnes opened his chest and fixed one of the two defects in his heart. He went in there with a scalpel and did some kind of magic that I couldn't even begin to explain.

''He opened the valve, and the operation was a success. It was the longest three hours of my life.''

During the programme Jimmy thanked the Children's Hospital Los Angeles and the medical experts for taking care of his child.

William has since left the hospital to settle in at home with his family, and the funnyman has revealed his child is doing ''great'' following the operation and is doing ''all the things'' babies should do, including peeing on his mother.

He continued: ''He's doing great. He's eating. He's sleeping. He peed on his mother today while she was changing his diaper. He's doing all the things that he's supposed to do.''