The former Full House actor portrays a man who discovers he has a son and a granddaughter on his new comedy series Grandfathered, and he decided to take his co-stars Josh Peck and twin girls Layla and Emelia Golfieri, who share the role of young Edie, for a family outing to the California theme park last year (15).

However, John, who is currently single, was left red-faced after his attempt at chatting up a flirty fan during the trip backfired.

"Here's why I took them: babies are a great chick magnet...!" he tells late night host Jimmy Fallon. "I was carrying, I think it was Emelia, on my shoulder and I see a girl, she was flirting and she wanted to take a selfie... I went over to hit on this girl and the baby peed - I felt a warm feeling - all down my shirt."

John, 52, may have also been using the family outing as practice for the future after previously admitting children are the "only thing that's missing" from his life, and confessing working on the show has made him more eager than ever to become a dad.

"My ovaries are rattling," he joked to UsMagazine.com in September (15). "Do men have ovaries? They're jingling. I can hear them jingling now."

But the actor shocked fans this week (begs04Jan16) when he revealed he almost became a father in his 20s, after a woman he was dating aborted his baby.

"This was just bad timing," John told U.S. shock jock Howard Stern. "It really wasn't my choice... I think it was sort of a mutual decision."

John was previously married to actress Rebecca Romijn, but the pair divorced in 2004. She went on to wed another actor, Jerry O'Connell, the father of her seven-year-old twin daughters, Dolly and Charlie.