Praising Kimmel's son, Harris added, "Billy is a brave little boy and it's just heart wrenching, literally, and I'm so glad he's doing well."
Kimmel's wife, Molly McNearney, who is also the head writer of JKL, also tweeted about her son's recovery. "My baby is recovering from open heart surgery but I just woke up in a full blown panic that I forgot to move my toddler’s elf on the shelf," she quipped.
The good news comes just a day after McNearney spoke with The Hollywood Reporter and gushed over her husband's monologue, where he opened up about their son's health battle.
"I was still getting all of my work emails, and I didn't get one with the monologue for that night. I emailed Jimmy, and he said, 'I just want you to watch.' So, there I am, in my living room breastfeeding Billy with my mom beside me, and we're watching," she recalled. "I sobbed through the entire thing. I couldn't believe the strength that it took to tell that story a week after it happened. He didn't have to do that."