Last April, New York Jets quarterback Mark Sanchez, 23, was leaving the “Saturday Night Live” after-party in a Lexus sedan. He folded his 6-foot-3 frame into the back seat of the car and was followed by a parade of young beauties who squeezed in behind him.
“It’s like a clown car,” said an observer, mouth agape as the number of girls piling into the narrow back seat grew to six.
The incident, captured on a video that went viral on the Internet, seemed to confirm what football fans wanted to believe: Sanchez was the Big Apple’s party-boy bachelor — heir to the nightlife throne of “Broadway Joe” Namath.
Sanchez knew better.
“It looked a lot more scintillating than it was,” he confessed to a confidant.
The first girl who hopped into the car was his closest friend since high school, Rebecca Resnik, the Sanchez pal told The Post. The rest were Resnik’s friends. There was no canoodling in the back seat that night, no wild debauchery in a swanky hotel.
But Sanchez begged his friends not to tell anyone the truth.
“I’m happy everyone thinks that, because it makes me look cooler,” he joked.
Like so many professional athletes, Mark Sanchez has a dirty secret. But it’s not a love child, steroids or dog fighting.
It’s that underneath his hunky veneer, he’s a total dork.
“His girlfriend is New York Jets football, and she’s a very jealous girlfriend,” said his confidant. “I don’t think he’s been able or ready to carve out time for anything except his job. He’s not dating right now, because he just loves football.”
Sanchez grew up in Orange County, Calif., and was the big man on campus at USC. He was a popular student-government leader in high school, and a communications major in college. He was called the “Mexican Jumping Bean,” even though the third-generation Mexican-American barely speaks Spanish.
He left college a year early to sign a five-year, incentive-laden deal with the Jets that could be worth up to $60 million.
His huge contract, good looks and rifle arm immediately drew comparisons to Namath, another heralded and handsome bonus baby drafted by the Jets. And like Namath, who led the team to its only Super Bowl victory in 1969, Sanchez is seen as a winner — only the second rookie signal-caller in history to win his first two playoff games, and the poised leader of a squad that came within a game of the NFL’s championship.
So how has New York’s most eligible athlete (sorry, Derek Jeter fans) spent his off-season?
The highest-paid Jet could afford a private plane and a penthouse apartment overlooking Central Park — but instead, Sanchez drives around in a Toyota Land Cruiser and lives with his brother Brandon in sleepy Bedminster, NJ.
Instead of jetting to Vegas with an entourage for his 23rd birthday last November, he enjoyed an evening of turkey legs and jousting at Medieval Times.
After a trip to Madrid with Brandon, which coincided with Spain’s victory in the World Cup, the Sanchezes came home filled with a different kind of football frenzy, and spent hours on their Xbox playing the FIFA II soccer game. The football star even brought the video game and his console to upstate Cortland, where the Jets are training.
His Twitter feed is awash with goofy facial expressions, teenspeak and posts asking what Disney film he should rent that night. “Lion King? Aladdin? Jungle Book? Peter Pan? Help?” Seriously.
His biggest fear in shooting “Hard Knocks,” an HBO reality show documenting the Jets’ training camp, is dropping an F-bomb and disappointing his proud mother.
“I don’t think he knows how big his profile actually is,” said another friend. “He’s very much the [Giants quarterback] Eli Manning profile — but cooler. He doesn’t seem to know that everyone in the room, wherever he goes, is like, ‘Holy s- -t, Mark Sanchez is here.’ ”
If fame and money and New York have changed Sanchez, the son of a fire captain, it’s only to transform him into a foodie and a music lover.
His favorite burger is at Le Parker Meridien, his favorite sushi joint is Nobu and he’s a regular at the Midtown steakhouse Del Frisco’s — in part because of its proximity to the Broadway theaters.
Sanchez has seen “Wicked,” “In the Heights,” “Rock of Ages,” “Billy Elliot” and “Memphis” multiple times, and friends say he often belts out show tunes in the car.
The quarterback even presented an award for “Memphis” at the Tony Awards last year.
Sanchez has been spotted partying at some of the city’s hotspots like Abe & Arthur’s, Monkey Bar and Rose Bar, but friends and observers said he’s not a big drinker.
“He doesn’t belly up to the bar and ask for the usual,” said the confidant. “He’s never really been a drinker, but the older guys on the team have recently been teaching him about red wine.”
His best friends on the team are tight end Dustin Keller, fullback Tony Richardson and center Nick Mangold, and he spends most of his time hanging out with his two older brothers.
There are women, of course. No amount of show tunes can keep a broodingly handsome quarterback single.
Since last fall, he’s been linked to 20-year-old blond beauty Jennifer Mueller, a track star at USC who lives in New Jersey; bartender and model Ariana Madix, 21, whom he reportedly picked up at the Midtown watering hole Johnny Utah’s; as well as celebs like supermodel Hilary Rhoda and, most recently, former “Sopranos” star Jamie-Lynn Sigler.
But Sanchez isn’t focusing on the ladies right now.
“Jamie-Lynn was very sweet,” said the friend, who spent time with the couple after they hit it off at a Tribeca Film Festival party. “But she’s almost 30 and she’s been married before, and they were just in different places. Mark’s 23, and just trying to make sure he doesn’t fumble the snap.”
The two remain close friends after splitting up a few weeks ago just before training camp, the source said.
His teammates, however, like to give Sanchez a hard time for his heartthrob status.
“He’s not meeting my daughter; she already thinks he’s cute,” said Jets backup quarterback and Sanchez mentor Mark Brunell, 39, about his college-aged daughter. “I like the kid, but I don’t like him that much.”
For his part, Sanchez doesn’t want to be seen as the young guy making daughters swoon — he’s eager to prove that all the money and all the hoopla surrounding him will ultimately translate into a Super Bowl ring. “I’ll be working every day, on and off the field, to justify this contract,” he said last year.
So far, he is holding up his end of the deal.
Three weeks before training camp, Sanchez — who had off-season knee surgery — worked out twice a day with longtime trainer Todd Norman in California.
“It’s always been expected of him that he’s going to be great, and he always knew it in his mind, too,” said Norman. “But he’s never been one to be full of himself. He’s just a kid from Southern California with a huge work ethic. He’s the first guy I’d want next to me on the front line of a battlefield.”