It takes a special kid to play Billy Elliot, the English boy who gives up his boxing gloves for ballet shoes in the smash musical that conquered Broadway in 2009 and scooped up 10 Tony Awards.

For the show, based on director Stephen Daldry’s popular 2000 film, Billy has to appear to be 12. He’s got to master an extended tap solo and graceful ballet steps and make it all look new, going from rough-hewn to Royal Ballet-ready over the course of three hours and a few Elton John songs.

Billy must have the acting chops to convey sorrow and loneliness, anger and disappointment, triumph and joy. Billy’s also got to nail the working-class Geordi accent of a north England coal-mining town. Billy’s got to sing. And when Billy grows too tall or his voice becomes too deep, it’s bye-bye, Bill.

Now multiply this by the four Billys that it takes for every show, including the national tour that plays the Fox Theatre March 13-18, and you get an idea of the depth of teaching, training and tutoring that goes into each production. Every Billy is a mix of clay and steel, easily molded into a figure of poise and determination by a retinue of directors and choreographers who watch his every move, from auditions to curtain calls.

New York casting director Nora Brennan canvassed the country "American Idol"-style, auditioning about 2,000 kids before she found Broadway's original three Billys. She estimates that she has seen about 1,000 more kids since then.

“Most of these boys have never sung in their life,” says associate choreographer Mary Giattino, who supervises the dance for the company of more than 40, including four Billys, two Michaels and 10 small girls. “They have never acted. They have never stood on the stage in front of thousands of people to actually carry a plot.”

That pretty much describes 14-year-old Kylend Hetherington, a Michigan native who has worked his way up the Billy chain since joining the Broadway company three years ago.

“Before ‘Billy Elliot,’ I had never sang or acted. I was purely a dancer,” says Hetherington, who started dancing at 4 and played the smaller roles of Tall Boy and Michael on Broadway before being cast as a lead in the second tour national in 2010.

Since its arrival more than a decade ago, “Billy Elliot” has become a pop-culture phenomenon. The film struck a chord with audiences and raised awareness of the bullying that often goes hand-in-glove with being a young male dancer. In the story, Billy has lost his mother and in the hard-scrabble world of his coal-mining community, circa the 1980s, he struggles with his identity.

The musical version of “Billy,” with songs by part-time Atlantan John and book by the movie’s screenwriter, Lee Hall, opened on London’s West End in 2005. A Broadway production appeared in October 2008 and the image of Broadway’s first three Billys picking up their Tony Awards was a memorable Tony moment.

Hetherington says the show resonates with youngsters struggling to define themselves.

“I can relate to it,” he says. “When I started to dance, I got bullied. I got teased. I got people who told me this isn’t what I’m supposed to be doing and this is stupid. Like Billy, I had to push through.”

Besides Hetherington, the tour’s other Billys are Ty Forhan, Zach Manske and J.P. Viernes. The actors travel with a parent or guardian, plus three tutors. The boys split their eight shows a week so that each does two performances. If the scheduled Billy is sidelined by an injury or sickness, another boy is standing by to go on, sometimes on very short notice. It is a long and taxing show, nearly three hours, and on occasion, if something goes amiss, a second Billy might go on after intermission. For these reasons and to avoid disappointing fans, audiences never know which Billy they will see until just before curtain.

Currently, there is only one “Billy Elliot” in North America; not long ago, there were three. “We had about 12 Billys going at all times,” Brennan says. At that time, the producers ran a so-called Billy Camp in New York to keep a steady supply of boys waiting in the wings.

But just as quickly as the kids come into their own, they inevitably outgrow the part. That fact, plus child-labor laws that determine how much time kids can work and go to school while performing, have ensured that there has been a steady stream of Billys since the show was unveiled.

Brennan calls the brief shelf life of the average Billy "a slice in time."

“They know this going in. Everybody knows it," she says. "We all hate the day it actually happens and they have to leave. Some boys may not grow for six months and then some may grow four inches in six months. They just shoot up. It’s always a big shocker when that happens.”

Says Hetherington: “If you are taller than the person playing the dad and your voice is lower than his, that’s just not right.”

It takes a mature kid to play Billy Elliot. Wise beyond his years, he knows his moment is short and sweet. He knows when it's time to dance and when it's time to go.

Theater preview

“Billy Elliot”

March 13-18. $28-$73. Presented by Broadway in Atlanta, Fox Theatre, 660 Peachtree St. N.E., Atlanta. 1-800-982-2787; www.broadwayinatlanta.com.