"I love night shoots. Everybody else is [tired] by like two, three in the morning, which is weird because I'm the old guy!" Facinelli tells PEOPLE at the Los Angeles premiere of Ghosts of Girlfriends Past on Monday night.
"They should be the ones that should be like party hardy all night long," jokes the 35-year-old of his young costars including Robert Pattinson, 22, Kristen Stewart, 19, and 17-year-old Taylor Lautner. "At five in the morning I was like, 'I could go another 10 hours!' And they were like, 'Crash!' "
Also up for around-the-clock action: fans, who have been camping out on the Vancouver set despite the less-than-welcoming weather.
"The first [film] we were just hoping people went to see it. We knew there were diehard fans and those are the ones we're like, 'Let's make a good movie for [them],' but we didn't know the diehard fans were going to explode into the amount that they did," he says. But the father of three insists he's nothing but grateful for the fan-demonium. "I feel loved by so many fans, like I went to Disneyland the other day, and I took like 100 pictures just walking like 10 feet … you want to give back to them."
Next up, Facinelli will play another kind of doctor in Nurse Jackie, a Showtime dramady debuting in June. How did he prepare to play the "quirky" character, who inappropriately grabs costar Edie Falco? "I did do a whole class on boob grabbing!" he says with a laugh. What did wife Jennie Garth think about that? He teases, "[I told her], 'You're my test subject!' "