Leighton Meester is a rich Manhattan teen in ‘Gossip Girl’

NEW YORK - “Gossip Girl” star Leighton Meester is cooling her heels. No, not the black patent heels she’ll be perched high atop for her first scene of the day. That’s hours away.

Right now, she’s passing time, barefoot, in a trailer parked off bustling Madison Avenue in midtown Manhattan.

When she gets the call, she’ll report for a 90-minute hair-and-makeup session in another trailer a block from here.

Then, returning, she’ll slip into a white Thread Social eyelet mini-dress, floral-knit black tights and those T-strap pumps — just the thing for a swank Sunday brunch, as staged by her new CW drama at the New York Palace Hotel up the street.

It’s about 7 a.m. on a bright, sunny July morning, and Meester is bright and sunny, too, having arrived a few minutes earlier wearing a lavender sundress.

White noise wheezing from the trailer’s air conditioner does a pretty good job masking traffic outside, “but I keep realizing: I’m on the street in a box!” Meester laughs. “Like they say: The acting is for free. I get paid to wait.”

True enough. But Meester’s wait could be just about over. Born in Marco Island, Fla., and raised in New York before moving to Los Angeles, the 21-year-old actress got her start as a child model. She has appeared on series including “Shark,” “House,” “24” and “Entourage.” Two seasons ago she was a regular on the short-lived NBC drama “Surface.”

But now she’s stepping into the high-profile, high-style role of Blair Waldorf, a scheming good girl who shares the luxe life with other fabulous Upper East Side prep-school teens. It’s the sort of role, on the sort of show, that could make a household name out of Meester, along with her costars Penn Badgley (who plays Dan), Chace Crawford (Nate), Ed Westwick (Chuck) and Taylor Momsen (Jenny).

And don’t forget Blake Lively, who plays Serena van der Woodsen, a notorious party girl now haunted by regrets. Serena is Blair’s best friend and worst rival.

How apt that, for the show’s location shoot, Lively occupies the other half of this trailer. SERENA is inscribed on her door, just like BLAIR is on Meester’s.

The series is based on the popular “Gossip Girl” young-adult novels. But its transition to TV is thanks to Josh Schwartz and Stephanie Savage, the creative team behind “The O.C.”

“I think the show will be relatable to lots of girls and even grown women,” says Meester confidently. “And a guilty pleasure for guys!”

Here is a TV show whose narrator, like the novels’, is an unidentified text-messaging guru. Gossip Girl, whoever she is, has her finger on the pulse of this trust-fund set — the loves, ambitions, feuds and wretched excess. As voiced by Kristen Bell (“Veronica Mars”), Gossip Girl’s blogging keeps everybody in the know, while keeping everything stirred up.