During a live national broadcast in the last moments of Dec. 31, a rapt Argentina watched its favorite son, Julio Bocca, glide through a poignant tango ballet on a stark white platform in Tierra del Fuego. As the clock struck midnight and the image of the spinning dancer was transmitted to television screens around the globe, Bocca's graceful steps became as much a harbinger of the new millennium as, say, fireworks dancing over the Eiffel Tower.

But then, Julio Bocca is no ordinary dancer.

In a country loaded with traditional machismo, the 32-year old Bocca has broken the norms of male success: He achieved national hero status as a ballet dancer. He's a huge mainstream star, as revered as any sports figure. He's a sought-after TV pitchman. He fills arenas usually reserved for pop stars. And in a place where masculinity had been defined by the brusque former president Juan Peron and swaggering soccer great Diego Maradona, Bocca's success has even generated a surge of male enrollment in Argentine ballet schools.

A winner of the 1985 Gold Medal at Moscow's International Ballet Competition, Bocca was chosen at the age of 19 by Mikhail Baryshnikov to become a principal dancer for the American Ballet Theatre. Bocca still dances the New York season with ABT, but in recent years he's branched out. Next month he'll perform in "Fosse," a new Broadway musical based on the work of choreographer Bob Fosse. Bocca made his screen debut in last year's Academy Award-nominated film "Tango."

And back home, the diminutive dancer is being recognized for accomplishing something else: Bocca, observers say, has taken the snobbery out of ballet and made it appealing to the average person, particularly easily bored youths of the computer generation. Indeed, Bocca's fusion of ballet with tango and rock has, like the film "Shakespeare in Love," made old, stodgy art appeal to young people. Though he studied classical ballet at Buenos Aires' traditional opera house Teatro Colon, he has taken the dance out of its gilded halls and literally into the street, performing free concerts for audiences of more than 100,000.

"I adore him! We go to see all of his performances" in Buenos Aires, says Laura Lo Bianco, 19, thumbing through Bocca T-shirts on sale at an exhibit on the dancer at the Palais de Glace. There one can see everything from Bocca's childhood "Six Million Dollar Man" doll and his first ballet slippers to videos of him performing at Milan's La Scala and London's Covent Garden. "At the last performance we went to, he began by dancing a piece from 'Giselle,' and then went immediately into Pink Floyd," she adds. "It was one of the coolest things I've ever seen."

Culture experts here say Bocca broadened the appeal of ballet with nontraditional audiences by taking Argentina's melancholy tango and fusing it with classical dance. He is interpreting the mix through his own company, Ballet Argentino, which is touring extensively in the United States, Europe and Asia. But Bocca, who is self-effacing and quick to laugh at himself, has also scored points by being outrageous. He posed with one of his frequent dance partners, Eleonora Cassano, in a spread for Playboy magazine. In slick ads for Dannon yogurt, he dances classic ballet and flexes his well-strung torso to pop music, shirtless in flesh-colored leotards on the rooftop of a Buenos Aires skyscraper.

"In Argentina, Bocca is not a man, he is a phenomenon," says Jorge Fama, executive director of ballet at the Teatro Colon. "We've had great dancers before, but Bocca is something entirely different. He's a sex symbol, a role model and a mainstream star. And he's the person who reinvented ballet here as pop culture. . . .

"He's also changed the way our society views men and ballet," adds Fama. "The association for any male dancer used to be, 'Oh, he's a ballet dancer, look at the that gay guy!' But now, they say, 'Oh, look at that ballet dancer, he's rich and internationally famous!' "

This year almost 15 percent of the students in some classes at Bocca's Buenos Aires dance studio are male--something ballet directors say was unheard of 10 or 15 years ago. At a recent session, astronomy student Juan Descalzo, 23, stood amid a sea of little girls in tutus in an intermediate ballet class, chewing on his tongue as he attempted an awkward plie.

"I thought it would be fun," said Descalzo, who took his first ballet class with his girlfriend four months ago. "I've seen Bocca dance, and I really respect what he does. And it's a great way to exercise, so I figured I'd give it a try."

Bocca's mother, a ballet teacher, gave him his first lessons when he was 4. "I was just a little kid who enjoyed the music and getting into the costumes," he says. "It was like getting dressed to go to some great party. It was just, like, cool."

He never met his biological father. His mother's father, a night watchman in a Buenos Aires factory, helped raise him--and encouraged Bocca to respect classical ballet.

At the epicenter of this city's rich tradition of classical arts, cultivated by the European immigrants whose descendants today largely populate Argentina, stands the Colon, where instructors noticed Bocca's talent and accepted him as a pupil at age 10. Nevertheless, those were difficult times to be an Argentine boy who wanted to be a ballet dancer. During the harsh military dictatorship that lasted from 1976 to 1983, Bocca remembers being stopped and questioned by authorities on his way home from the Colon. "I couldn't tell them the truth, that I was coming back from my classes where I was studying to be a ballet dancer," he says. "Forget it"--here he makes a gesture suggesting he would have been beaten--"I never would have made it home."

If his mother and the Colon instructors made Bocca a dancer, it was Moscow that made him a star. In 1985 he made his way to Moscow for the celebrated international dance contest there and danced "Don Quixote." He won the top prize and within a year became a principal dancer at the American Ballet Theatre.

At home, where the dictatorship had ended and Argentina entered into a massive cultural and social reawakening, Bocca was quickly embraced as a hero. And critics both in and out of the country fell in love with Bocca, who, at 5 feet 6 is shorter than the average male dancer.

"He made up for that in technique and stage presence," says New Yorker dance critic Joan Acocella. "But what is really ravishing about Bocca is not just his virtuosity, which is very great, but his hunger and avidity, his joy in being onstage. He always seems to be in love with the woman he dances with. Oh, he is a wonderful Romeo."

But Bocca is more concerned with ordinary people than he is with critics. "If they love me, I'm lucky," he says. "It was always my intention to please audiences, especially at home. Anything else would have been failure."