More than a million copies of "Heaven Is for Real" are in print. It hit the top of the New York Times best-seller list for paperback nonfiction. This week, the movie based on the book, starring Connor Corum as Colton Burpo, whose experience inspired the book, and Greg Kinnear and Kelly Reilly as his parents, was released in theaters.

"When my son started sharing with me about heaven, that was 11 years ago," Colton's dad, Todd Burpo, said during a recent tour stop in Atlanta to promote the movie. "I really am surprised so many other people are listening to my son."

Colton was 4 when he underwent emergency surgery following a burst appendix. After his long recovery, the family happened to drive past the hospital.

"We said, 'Hey, Colton, do you want to go back?'" Burpo joked. In typical little-brother style, Colton volunteered his sister for a trip to the land of beeping machines: "No, Dad! Send Cassie!"

Then he added, “‘That’s where the angels sang to me,’” Burpo said. “We were like, what? We don’t talk about angels in our house.”

Colton later revealed other experiences he had during his time on the operating table.

“You had a baby die in your tummy, didn’t you?” the child once asked his mother. The Burpos had never told him about Sonja’s miscarriage. He would go on to discuss details of heaven and said he sat on Jesus’ lap.

“It was really hard to comprehend,” Burpo said. “He said he was gone three minutes but yet he saw so much. I had never encountered a near-death experience like this on a personal level. No one in college, no one in my life had prepared me for how you ask your 4-year-old about heaven.”

Burpo is a pastor who also works as a volunteer fireman and garage-door installer in the family's rural Nebraska town. He shared Colton's story first from the pulpit, then embarked on the book project. Critics soon abounded. ("Heaven Is Real, but 'Heaven Is for Real' Is Really Not" is the title of an essay by author Hank Hanegraaff.)

“Colton’s reaction to skeptics is the right one: Heaven changes everything,” Burpo said. “Colton’s personal experience confirms Scripture. Jesus tells his disciples, ‘You must become like a child.’ Jesus didn’t tell children, ‘Grow up and become cynical adults.’”

Living in their small town helps keep the family grounded and, Burpo says, lends credence.

“There’s no way you can live in a town of 2,000 people and make something up and get away with it,” he said.

Colton is now a high school freshman who discusses heaven like other teens might discuss sports scores or weekend plans.

“He started talking about heaven in kindergarten,” Burpo said. “He’s no superstar.”

The family has been thrilled with the success of the book and now the movie, which The Hollywood Reporter said debuted Wednesday with a box office haul of $3.7 million from 2,417 theaters and “could gross north of $20 million by Easter Sunday, one of the top openings ever for a faith-based title.” But Burpo’s faith journey isn’t over.

“Something broke inside of me when I saw my son almost die,” he said. “I’m still not sure it’s fixed yet.”