Matthew Morrison, star of Fox's monster hit Glee, pulls up to his former high school, slides his old-Hollywood-style sunglasses down his nose, and scans the parking lot with his piercing green eyes. No spaces. A burly security guard in a yellow safety vest walks toward his Audi coupe. When the guard recognizes Morrison's signature wavy locks and his chiseled features, he melts. "Mr. Morrison! I didn't recognize you! I didn't know you were coming." The man is a stranger, but he's a fan. A big fan. He points Morrison toward a VIP spot in front of the school's steps. As Morrison parks, the guard trails after the car, gushing. "I'm a total Gleek, man. I love your show. I've even got a Glee bandanna. Oh, man. Wow."

"Crazy right?" Morrison says to me, a tight little smile on his face. You never know who loves musical theater these days, thanks to Glee, the saccharine-sweet, campy-but-commercial celebration of life inside a high-school song-and-dance troupe. At times the music-punctuated melodrama verges on being a sort of psychedelic after-school special. Morrison, of course, plays Mr. Schuester, the earnest, curly-haired teacher who wants to change his students' lives through the power of performance. Since the show went on the air, in May 2009, occupying the coveted time slot after American Idol, Morrison has become a kind of hero to TV audiences as he judiciously manages the young dreams of his pupils, brokers teen conflict, and occasionally busts into righteous covers of nineties hits—think Vanilla Ice's "Ice Ice Baby" or Bell Biv DeVoe's "Poison." And now, somehow, a stocky school security officer who by the look of him should be tuned into ESPN is obsessed.

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Today Morrison, who's 32, is wearing perfectly faded jeans, a red flannel shirt, and Prada laceless oxfords. He's marching through the halls of the Orange County High School of the Arts, where his fame was based entirely on his abilities to belt out show tunes and perfectly execute all the cheesy dance moves of the mid-nineties while Rollerblading to class and dating the head cheerleader.

He is momentarily anonymous as he passes students lost in gossip, text messages, teen ennui. Then it starts, with a few inhaled gasps. "Wait, is that..." A stuttered chorus follows: "Ohmygod-ohmygod-ohmygod." Vans sneakers squeal to a halt on the hallway floor. "From Glee, ohmygod! From Glee! It's Matthew Morrison!" Morrison looks down the hall and realizes that class has just let out. He starts to walk a little faster.

"OHMYGOD!" Suddenly the throng erupts. Students start shrieking to each other and to themselves. Hair is tossed, shoulders jostled. Cell phones come out with gunslinger speed and are aimed at Morrison. He tries to be gentle as he presses forward through the wall of fandom. "He's just a person!" shouts one miffed boy, but his logic is drowned out by the collective ecstasy at being in close proximity to Mr. Schue.

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One of Morrison's former teachers, Ralph Opacic, now the principal of the school, takes him by the shoulder and guides him toward his office. He pushes open the doors, and Morrison is welcomed into the safe bosom of the matronly secretarial staff. The actor laughs and pants, a little out of breath. The ladies turn to one another: "I've never seen anything like that." We can still hear the ruckus outside—the thunk-thunk of bodies against the office doors. Then the receptionist turns to Morrison and, as the rest of the middle-aged administrative staff encircles him, asks, "Matt, sorry to be a bother, but can we get a picture with you?"

•••

To star in Glee is to enjoy a special kind of fame. The show is not just an international phenomenon or a merchandise-franchising factory or a hothouse that has placed a record-shattering number of singles on the Billboard Hot 100—though it is most definitely all those things. The brainchild of Nip/Tuck creator Ryan Murphy, Glee continually tackles taboos: a wife who fakes a pregnancy for months and months; a knocked-up cheerleader who lies about her baby daddy to the real baby daddy; the awkwardness of cheerleader-paraplegic sexual relations; not to mention narrative plot points that deal with dead parents, gay adoption, coming out, and the perils of unchecked ambition. Mercifully, the drama is leavened by regular musical interludes, in which the hot young cast breaks into jubilant song-and-dance performances of hits by everyone from Jay-Z to Journey. Musicians like Billy Joel and Lady Gaga line up to have their songs covered, stars like Gwyneth Paltrow vie to appear as guests, and TV audiences sing along in numbers so unprecedented they're giving new life to the moribund music business. All of which means that the past 18 months have been pretty damn dizzying for Matthew Morrison.

Today is no exception. While Opacic reminisces about the talented and polite kid Morrison was in high school, the girls in the hall are throwing themselves against the office window. "For his age," Opacic says, "he was a very dynamic performer." Cell-phone flashes blaze. "For our kids, Glee is their dream," Opacic continues as his secretary gets on her walkie-talkie to call security. "It's their lives. Usually TV and movies celebrate football players and cheerleaders." Soon a couple of security personnel disperse the mob and Morrison is ushered down the hall in peace to watch the school's show choir perform.