Jimmy Kimmel's baby son has 'successful' second heart surgery

Chris Pratt, Melissa McCarthy Set to Guest-Host Jimmy Kimmel This Week

Jimmy Kimmel's Son Billy Is Recovering From His Second Heart Surgery

Jimmy Kimmel Live! turned to celebrity guest hosts this week as Jimmy Kimmel is at home with his family after his infant song Billy 's latest heart surgery, which took place Monday morning and was successful. The newborn had open-heart surgery a few days after he was born.

The network also announced that Billy's dad is taking a week off from "Jimmy Kimmel Live!" to tend to what's most important to him.

Billy's experience prompted Kimmel to use his show as a platform to advocate for every family's access to equal medical care, including those unable to afford it.

During his opening monologue, Pratt admitted that he's nervous about being Kimmel's replacement.

Pratt was game, starting out a bit wobbly on the first verse before Stapleton came in blazing, his soulful wail lifting the otherwise sub-karaoke bit high into the air.

"For me, it's inspirational to see a guy with a huge beard and a cowboy hat to finally make it in country music", Pratt joked of Stapleton during his introduction. The two ended up using a green screen that made it look like the actor was lifting the singer effortlessly.

Wednesday: Neil Patrick Harris will be guest host. Melissa McCarthy will replace Kimmel on Thursday.

Weather warning issued with snow forecast this weekend