Jimmy and Molly's second child, a son named William, or "Billy," was born on April 21, 2017. After his birth, the normally lighthearted and funny late night host started his May 1 episode with a 13-minute monologue revealing that Billy was born with a rare and scary heart defect that involved him getting open-heart surgery at just days old.
In August of that year, he gave an update on Billy's health, saying that he was "doing great," and in December the little guy had his second open heart surgery, which also went well. On his son's second birthday, Jimmy shared the above photo of Billy with the caption: "Happy 2nd birthday to our little #Easter buddy Billy. We are grateful always to the nurses and doctors at @CedarsSinai & @ChildrensLA who saved his life and all of you who prayed & sent positive thoughts our way."