Their sonWilliam “Billy” Christopheris now a year old, butJohn Stamosand his wifeCaitlin McHugh Stamoswon’t soon forget the memorable way he entered the world.

“It all started when [Caitlin] had contractions, [but then] we went to the doctor and he said, ‘It’s not ready, why don’t you go home and have a glass of wine?’ ” Stamos tells PEOPLE forThe Beautiful Issue, on newsstands Friday.

“She normally doesn’t drink, and hadn’t drank for nine months … she had one glass of wine and she was hammered,” he jokes of his wife.

Recalls Caitlin, “It was really funny. I get to the hospital and I said, ‘I already had a glass of wine, now it’s a party!’ Then theygave me the epidural and Iwas laughing all over the place.”

John Stamos (R) and wife Caitlin with son Billy.Brian Bowen Smith

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Still, despite the celebratory mood, Billy arrived nearly six weeks early — and Caitlin and theFuller Housestar, 55, reveal that it took time to adjust.

“He wasn’t fully baked, so that was very scary in the beginning,” says Caitlin. “He was very, very small … fragile, little. Every time [he] fell asleep, you’re like, ‘Please wake up.’ [We were] constantly checking to make sure he was still breathing.”

But parenting came pretty easily tothe couple, who wed in 2018, two months before Billy’s arrival. “I waited a long time for a kid,” says Stamos. “I just had to meet the right person to do it with, and to straighten my life out. I was always meant to be a father, I think.”

Adds his model and actress wife, 32, “He’s a natural. He would joke around about how he wasnever going to change a diaper, but he’s pretty good at it!”

John Stamos/Instagram

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And these days, Billy is keeping them busy — and entertained.

“He’s such a happy, giggly guy,” Caitlin tells PEOPLE. “Fake sneezesmake him laugh. Butnot real sneezes. Real sneezes kind of freak him out.”

Quips Stamos, “And he’s a hambone. I don’t know where he gets it from!”

For more from John Stamos and other celebrity families, pick up The Beautiful Issue ofPEOPLE, on newsstands Friday.

source: people.com