Surgeon who performed open heart surgeries on Jimmy Kimmel’s son speaks out

The lead surgeon who performed all three heart surgeries on Jimmy Kimmel’s son Billy at the Children’s Hospital Los Angeles shared new details about the 7-year-old boy’s heart condition, operations and recovery.

In an interview with “Good Morning America,” Dr. Vaughn A. Starnes told ABC News’ Matt Gutman that Kimmel and his wife Molly McNearney did not know about their son’s heart defect until shortly after he was born. Kimmel gave his permission to Starnes to do the interview with "GMA."

"It caught them by surprise," Starnes explained. "They thought Billy was going to be perfectly normal and was until two or three hours after delivery. That's when the nurse noted that the child was somewhat blue and sounded the alarms."

He added that the experience has "got to be the most scary, terrifying thing that a parent goes through."

Billy Kimmel has a condition called Tetralogy of Fallot, a congenital heart condition where a combination of four heart defects affects normal blood flow through the heart, causing oxygen-poor blood to be pumped out to the body. It typically requires surgical intervention in infancy or early childhood to improve blood flow and oxygen levels.

Starnes noted that Billy "had a very severe form" of the condition.

"He had no connection between the right ventricle," he said.

Last month, Kimmel provided a health update on Billy via Instagram after his son's third open heart surgery.

In the post, he detailed his son's operation and thanked the medical team for their work.

The latest procedure was required to insert a valve that could help Billy live normally and it still came with a risk.

Discussing the mood of Jimmy Kimmel and his family going into the surgery over the Memorial Day weekend, Starnes shared that "Jimmy was very emotional. And Molly [McNearney] was obviously emotional, but more in control of her emotions."

Nevertheless, Starnes said the surgery was an instant success.

When Billy returned home from the hospital last week, Kimmel shared a video that his wife recorded of him in the kitchen holding a broom and attempting to encourage a hawk that had flown inside their house to fly back out.

The bird of prey fumbled in the corner of the glass windows as Kimmel attempted to usher it toward an open window before the hawk flew across the kitchen, at which point Billy could be seen moving quickly to go upstairs before the bird eventually flew out the sliding glass door.

During the conversation with Starnes, Gutman pointed out how Billy was acting like a completely normal kid in the clip after undergoing his heart surgery.

Asked if Starnes was surprised that Billy was able to be so active upon his return from the hospital, Starnes replied, "A little bit."

"I knew after putting a valve in there, he would improve. I didn't expect him to improve that fast," he said.

Starnes also opened up about the rewarding feeling that comes with witnessing progress from Billy or any of his patients who are no longer struggling after their surgery.

"It’s the greatest joy that I have," he said. "After 30 years … it never gets old."