Kimmel's infant son Billy is "recovering well" after his second heart surgery earlier this week, Harris said.
“I’m thrilled his son Billy’s heart operation was a success. He is recovering very well. Jimmy told me today that the respirator is out,” he said. "He is eating, he is smiling."
Harris continued, "So, all good news. We are sending lots of love to the Kimmels. Billy is a brave little boy ... I'm so glad he's doing well."
This new update comes a few days after Kimmel's show rep told ABC News that Billy had undergone a "scheduled and successful" heart surgery.
The representative added that the late-night host, 50, would take time off to be with his family. Guest hosts like Harris will be filling in for Kimmel.
Fans, friends and family have been supporting Kimmel since May, when he opened his show with the emotional story about Billy's heart defect and emergency life-saving surgery.
Since then, Kimmel has been very outspoken in favor of making sure Americans, especially those with pre-existing conditions, have access to medical care. He's even waded into the national health care debate.
Kimmel's wife, Molly McNearney, told The Hollywood Reporter earlier this week that people ask about Billy all the time.
"We haven't gone to a coffee shop, filled up the gas tank, done anything without someone asking us how Billy is doing, and, thank God, we get to say something positive," she said.