08/22/2013 at 12:45 PM EDT
Helping a son prepare for his high school sports team is a proud moment for any father. But when Gilles Marini's teenage son decided to join the football team, there was just one problem: His father had "no clue" how the game was played.
"I have no idea about [American] football, no clue!" Marini, 37, told PEOPLE with a laugh while attending Wednesday's Los Angeles premiere of The World's End
with son Georges.
"For me, I'm like, 'I want to play 45 minutes straight like soccer,' but it doesn't work that way, and I'm learning a little bit more, but he would beat me, big time."
Fortunately, the handsome French-born actor
had the perfect people to call upon for a quick American football primer: former NFL players and fellow Dancing with the Stars
alums Emmitt Smith and Donald Driver.
"Donald said something that was very valuable." Marini says. He said, " 'Remember, in high school it's fun. Make sure that he reminds himself that it's supposed to be fun.' And Emmitt told Georges, 'Keep your head down, cover your chin, and run as fast as you can.' "
Besides learning a lot about football, the former Sex and the City
movie actor is also learning about the realities of watching your little boy grow up.
"You know you've become old, first of all, when you're son starts high school," Marini says as he pulls his son in for a hug. "And then when he starts playing a sport better than you can ... but he's very talented, and he never gives up on anything."
Reporting by REAGAN ALEXANDER