"Excuse me, excuse me," says a pair of brown orthopedic shoes attached to a plaid-skirted gargantua with tightly curled gray hair. "No one is allowed in the theater." That goes double for actresses. McAdams apologizes sweetly and, taking your hand, pulls you into the outer room toward two oversize club chairs by the windows, stepping between the roosters and turtles and squirrels and bears woven into the carpet. "I keep getting in trouble today," she giggly whispers. "I took out a book on slow cooking—you know, Crock-Pot? And I got a call this morning, 'Bring it back! The slow-cooker book is in demand! You have to bring it back.' And then I got pulled over by a cop on my way here for running a red light on my bike." She rode a bicycle, in a dress? "I did!" Her eyes dance. "And now we're getting kicked out of the kids' auditorium!" All before noon.

McAdams curls up in a corner of a big leather chair, making herself teensy in the process. Whistle thin, she has the diminutive dimensions of a figure skater—a former incarnation. That grounded weightlessness has served her in embodying a quick succession of disparate characters in highly successful films—the nasty teen queen in Mean Girls; the World War II-era ingenue in The Notebook; the action heroine in Red Eye; a winsome, woo-able bridesmaid in Wedding Crashers—the box office sum of which added up to "The next Julia Roberts!" or so the Tinseltown criers cried. "There's always that need to turn everything into something you can recognize," McAdams says, understanding the inclination without being so inclined. Beyond that, she can't explain herself, because she's not Herself, you see. But on-screen the two actresses do share a rare effervescent, incan­descent, superlunary power that prevails upon you to root for their happiness as if your very own depended on it. And it does. Who could stand to see Julia go back to hooking on Hollywood Boulevard or Rachel marry the one who isn't The One?

"You feel almost vulnerable watching them. They're giving you something so intimate," says Ira Sachs, who cast McAdams in the upcoming Married Life. "They take the everyday and turn it into something enormous."

"When Wedding Crashers came out, everyone was hyped up, calling Rachel the new It Girl," recalls Tom Bezucha, director of The Family Stone, in which McAdams costarred with Diane Keaton. "I felt anxious about that because it's so diminishing to her talent. You get the impulse—you want to put her in everything. But her selectiveness shows wisdom greater than her years about her place in the industry. She's very purposeful in side­stepping Hollywood. She has the opportunity to be this huge, huge movie star, but in her heart she's a character actress."

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