For even a seasoned talk show guest this would be unnerving. Thorne-Smith is referring to Brody's semisecret relationship with Rachel Bilson, who plays Summer on the show. Brown eyes agog, Brody nervously polishes off the rest of his Budweiser before leaving the dressing room. But when the 24-year-old actor bounds onto the set, girls wearing homemade I LOVE ADAM BRODY T-shirts start squealing Beatles fan-style, and he woos them with the panache of a high school BMOC slipping off a prom dress. “If anything I say tonight isn't funny, I'm gonna point to you and you have to laugh,” he instructs the audience. “Like, 'I just flew in from West Hollywood, and boy, my arms are tired.'” He points. They scream. When Kimmel brings up the dating rumor, Brody gives him an easy smile. “I work with some beautiful ladies,” he says with a shrug, like, Can you blame me?

Earlier that day, over lunch, I also asked about his love life. “Are you 'still' dating Rachel?” Brody repeated. “I like your phrasing.” It took a beat before I realized he was teasing me for being a cynic. In person, Brody comes off more cocksure than cocky. Like the character he plays, he's a wild gesticulator and speaks at a rapid clip that almost, but not quite, races past a slight lisp that on him is incredibly sexy. He's better-looking up close than on the teeny-tiny screen, fine-featured, with Crest-strip white teeth and a smattering of freckles. His brown hair is unself-consciously rumpled, tweaking out like a Gerber baby's, and he looks as though he doesn't dress up without a damn good reason (a wedding, a photo shoot), wearing a hoodie and Converse sneakers that have I Y YOU written on them in ballpoint pen.

Brody's confidence can put a woman's back up. “When we were shooting the pilot, Adam made a comment like, 'Hi, I'm the guy who's higher up on the totem pole than you,'” Bilson says with a laugh. “I was thinking, Ohhhkaaay, a--hole!” But he gets under your skin. After spending time with him, you tend to smile at not only what he said but the way he said it. Bilson admits, “When a guy can make fun of you, that's attractive. Who knew that teasing could have so much power over a woman?”

The O.C.'s co-executive producer Doug Liman did; he was convinced that Brody's self-assurance would emerge from beneath Seth Cohen's manic dorkdom. (Liman has a knack for giving the ladies what they want: He directed Vince Vaughn in Swingers.) “Girls think of Adam as a stud,” Liman says. (Seconds later he mutters, “There must have been a better way to say that.”) Josh Schwartz, The O.C.'s creator, compares Brody to a young Tom Hanks: great with an ad-lib, not too classically handsome, yet not so awkward that you couldn't imagine trying to seduce him. Brody fools us into thinking he's our own discovery, a catch whose appeal eludes lesser women. As the thinking girl's jailbait, he doesn't disappoint. Brody riffs on his obsession with indie rock (Death Cab for Cutie, the Shins), and like any self-respecting hipster, tells you that he plays drums in a band. (Don't try buying tickets—they keep changing their name.)

Four years ago, Brody—who was raised by a graphic artist (mom) and lawyer (dad) in a section of San Diego about 80 miles south, and light years away, from Orange County's Newport Beach—was lingering in obscurity in his hometown. His only aspiration was to own a surf shop; it wasn't until he was working at a Blockbuster that he looked at his roommate and said, “Have you ever thought about acting? I mean, we're not actually doing anything.” Success came fast: Brody went from parking cars at the Beverly Hills Hotel to a guest stint on Gilmore Girls, a bit part in The Ring, and a lead in the skateboard movie Grind. Now, thanks to The O.C., he's a teen idol.

“It's weird,” Brody says when asked what it's like to have women wear his name across their chest. “Girls always want a hug, and I'm not a very huggy person. I'll be standing at the Grove [a local mall] and there will be an assembly line of girls who all want an embrace, like I'm Santa.” Bilson says that when Nicky Hilton asked to meet Brody in a club last fall, he got unexpectedly shy. “Girls are just crazy for him,” she says. “I can't blame them.”

When asked if he's concerned that he'll be associated with the same character for life à la Jason Priestley, Brody just laughs. He already has a small part as a kidnap target in Angelina Jolie and Brad Pitt's upcoming film Mr. and Mrs. Smith, about a bored couple who are hired to kill each other—although, he says, the way people are building it up you'd think it was an “Adam Brody-Brad Pitt buddy-cop movie.” In the meantime, he's looking forward to the inevitable Saturday Night Live spoof. “I saw an SNL where they played James Van Der Beek with the biggest bald spot ever,” he says. “It was a-mazing.” Then oh so fast, Brody takes charge of how our meeting will end. He leans forward, and my heart stops as he does what an idol does best: He hugs.