Jimmy Kimmel's son Billy's second heart operation has gone ahead successfully.

The 50-year-old talk show host and wife Molly McNearney welcomed their second child William John, known as Billy, into the world seven months ago, and were devastated to learn he had to undergo life-saving heart surgery after doctors discovered he had a congenital heart defect, but surgery went well on Monday (04.12.17).

ABC released a statement, saying: ''Jimmy's son Billy had a scheduled and successful heart surgery this morning.''

The network also announced that Jimmy will be taking time off to spend with his family and 'Jimmy Kimmel Live!' will be hosted by a series of celebrity guests this week.

Chris Pratt took the chair on Monday to interview 'Suicide Squad' star Margot Robbie and country singer Chris Stapleton.

Jimmy tweeted: ''Very thankful to Chris @PrattPrattPratt for filling in for me tonight with guests @MargotRobbie & @ChrisStapleton. You are Lord of Stars on the screen and off. (sic)''

Billy - who was born with Tetralogy of Fallot (TOF) with pulmonary atresia - was originally scheduled to have his second heart operation in late October, but it had to be postponed because the family were suffering from colds.

Jimmy explained: ''Basically, the pulmonary valve was completely blocked and he has a hole in the wall between the left and right sides of his heart.''

Billy will still have to undergo a third operation in the coming months.

Jimmy - who has kids Katie, 26, and Kevin, 24, with former wife Gina, and three-year-old Jane, as well as Billy, with spouse Molly McNearney - previously admitted he's nervous for the procedures and wants to get them ''over with''.

He said: ''We would like to get them over with and not have to think about it all the time, but it could definitely be worse.''

Despite Billy's condition, he is still a ''healthy and happy'' child.

Other stars due to guest host 'Jimmy Kimmel Live!' this week include Tracee Ellis Ross, Neil Patrick Harris and Melissa McCarthy.