John, 61, appeared on The Late Show with David Letterman to promote his new movie The Forger when he chatted about his youngest son.
Reflecting on whether or not the four-year-old understands that his dad is famous, John recounted a story where he and Ben were on a trip to the toy store when suddenly they were approached by fans clamouring for an autograph.
“I said, ‘Why are all these people wanting my photograph?'” John explained. “I didn’t know if he knew I was in films or not. He said, ‘Well, maybe they saw one of your movies!'”
Ben is the youngest of John’s children with wife Kelly Preston. His big sister Ella is 15, and the couple’s other son, the late Jett, who tragically died when he was just 16 in 2009.
Ben was the couple’s precious gift, conceived after Jett’s death, and the couple called him their little “miracle” as Kelly, now 52, conceived in her late 40s.
“Then he said, ‘I wanna work with you,'” John continued his story. “And so tonight, later, maybe, he could come on and say hi to you if it’s okay… If you allow him to.”
David was very keen at the prospect of meeting the youngster and exclaimed, “Bring him out now! Where’s the kid? Bring the kid out!”
So the cameras cut backstage where the youngster was waiting backstage in his mum Kelly’s arms.
But when Kelly put her son down, he seemed very shy about approaching his dad and David on the stage and ran off – bless!
Watch the adorable video in the player above