Jimmy Kimmel breaks down over newborn son's open heart surgery: 'We had atheists praying for us

Late-night host Jimmy Kimmel returned to television Monday night after a one-week hiatus and tearfully detailed the reason for his absence: His newborn son had open heart surgery on April 24 at Cedars-Sinai Medical Center in Los Angeles.

In an emotional 13-minute monologue, Kimmel revealed that his son, William "Billy" Kimmel, was born with a congenital heart disease. As a result, Billy required open-heart surgery to correct blocked valve in his heart.

"We had atheists praying for us," Kimmel said, choking up. "We had people who do not believe in God praying to him."

Kimmel explained that three hours after Billy was born, nurses determined that he wasn't getting enough oxygen in his blood, which alerted doctors that there was a serious larger problem.

"My wife [Molly McNearney] was in bed relaxing when a very attentive nurse at Cedars-Sinai hospital ... was checking him out and heard a murmur in his heart, which is common with newborn babies, but she also noticed that he was a bit purple, which is not common," Kimmel explained. "[Doctors] determined he wasn't getting enough oxygen in his blood."

After testing, hospital staff realized that the reason Billy wasn't getting enough oxygen in his blood was because the newborn had a blocked valve and a hole in the wall between the left and right sides of his heart. Billy was immediately rushed into surgery to correct the issue.

"It's a terrifying thing," Kimmel said about the moments leading up to the surgery. "I'm standing in the middle of a lot of very worried looking people.

"Not only did he get a bad heart, but he got my face," Kimmel joked.

Kimmel said his son's surgery was a success.  Kimmel and McNearney's son was able to go home just six days after his open heart surgery.

"Six days after open heart surgery, we got to bring him home, which is amazing," Kimmel said, smiling broadly. "He's eating, he's sleeping, he peed on his mother today when she was changing his diaper."

The Kimmel family still has a tough road to navigate, however. The late-night host revealed that his son will have to have a follow-up surgery in three to six months to mend the hole in the heart, and another "non-invasive" surgery when he's older.

Kimmel and McNearney announced in December that they were expecting their second child. The couple also has a 2-year-old daughter, Jane.

Watch the video below to see Kimmel's emotional response to the outpouring of love he received.