FROM BALLET TO BROADWAY: Adam Rogers, a member of the cast of “An American in Paris,” taught a dance sequence from the show to students at Princeton Dance and Theatre School on Sunday. (Photo by Risa Kaplowitz)

As one of two “swings” in the new Broadway show An American in Paris, currently in previews at the Palace Theatre, Adam Rogers is on stage as part of the male ensemble four times a week. But that doesn’t mean he has it any easier than the cast members who perform eight shows a week. In fact, his job is harder.

At any given moment, the 28-year-old dancer and singer can be given just a few minutes’ notice that he will be replacing one of the regular cast members who may have succumbed, mid-show, to a turned ankle, or maybe a bout of food poisoning. And Mr. Rogers, who must be in the theater at every performance, has to be ready to jump in, literally — to any one of four ensemble roles.

“You have to be really smart to be a swing,” he told a group of nine aspiring dancers at Princeton Dance and Theatre (PDT) school on Sunday. “I have 300 pages of charts that tell me where people stand, where they come in. And since the ensemble moves the scenery and the panels, I have to know all of that, too.”

Mr. Rogers, who performed in PDT’s The Secret Garden a few years ago, traveled from New York to the school in Forrestal Village on his day off to teach a master class containing a section from one of the many dance sequences in the show. The students ranged from a 10-year-old boy who is an international ballroom dance champion for his age group to an adult Pilates instructor. They learned quickly.

“You guys are picking it up faster than we did!” Mr. Rogers enthused. “It took a lot of us two weeks to learn this and get it right.” Flapping his arms and contracting his torso for one step that was repeated several times as part of the choreography, he told the students, “We call this Martha Chicken because it reminds us of Martha Graham and, yes, a chicken.”

The steps were relatively simple but very quick and precise. By the middle of the class, Mr. Rogers was sweating and so were his students. By the end, several of the students were performing the segment with ease. “Now if you go and see the show, you’ll recognize the choreography,” said Risa Kaplowitz, the school’s director and co-founder. “What a great experience.”

Though it doesn’t open officially until April 12, An American in Paris is currently one of the hottest tickets on Broadway. Set to an all-Gershwin score, the show is based lightly on the 1952 movie starring Gene Kelly. Christopher Wheeldon, a former ballet dancer, is the choreographer and director. The lead couple is played by two ballet dancers, Robert Fairchild of the New York City Ballet, and Leanne Cope of England’s Royal Ballet — the two companies with which Wheeldon performed — and the ensemble is made up of dancers who are either members of ballet troupes or have a strong background in the technique.

But they have to sing, too. Mr. Rogers told the PDT students he started learning to sing opera at age 11. Ballet lessons followed a few years later. He performed with the Kansas City Ballet, Sarasota Ballet, and Pennsylvania Ballet II before switching his focus to Broadway, landing roles in Cinderella and Chaplin before winning a contract with An American in Paris

Prior to Broadway, the show played two months at the Theatre du Chatelet in Paris, to rave reviews. “It was exhausting, but it was wonderful,” said Mr. Rogers. “I lost 10 pounds from all the work. But I’m not complaining. Each of us had a studio apartment five minutes from the Louvre. My dressing room had a balcony that overlooked the Seine. It was like a dream — but a really tiring one.”

Mr. Wheeldon is an accomplished ballet choreographer making his debut as a Broadway choreographer/director. “He’s so nice, and so patient. And he’s very clear about what he wants,” Mr. Rogers said. “The fact that he’s the choreographer and the director is really working well, because the show has amazing visuals that are so tied in to the dancing. You need someone who can see and understand both worlds.”

On matinee days, when there are two performances, cast members usually run out to buy food after the afternoon show, bring it back to their dressing rooms, and go to sleep before the evening performance. “It’s a very, very difficult show because there is just so much dancing in so many styles — tap, jazz, and ballet — and acting and singing,” Mr. Rogers told the PDT students. “It’s a marathon, and you have to learn to keep up your stamina. But it’s very rewarding.”