Adios, Macarena. Lambada who? A new, young audience flirts with the call of the jitterbug.

It’s a scene right out of a Gap ad. Only better. Beneath the brilliant blue-and-gold-painted ceiling of New York’s Supper Club ballroom, men — mostly in their 20s — are spiffed up in wide ties and suspenders, three-piece suits and zoots, fedoras, and black-and-white spectators. They slide across the dance floor, turning partners whose Mary Janes gleam as their ’40s-style dresses flare with the spins. Older couples are on hand, but they glide past their juniors with no generation gap in sight. As John Ceparano, the leader of the swing band the Jet Set 6, digs into ”The Lady Is a Tramp,” a friendly, spirited energy tears through the room.

Say what you will about the new swing revival: It’s just another dial-a-decade retro fad, selling more kitschy culture to susceptible poseurs. But in the last five months, swing has graduated from trumpeted trendlet to full-tilt movement. ”It’s one of those rare moments where you feel there’s a party going on and you’re jealous you’re not at it,” says Mike Tierney, VP of music programming at VH1, describing a recent swing concert he witnessed in Chicago.

No one knows for sure how many Americans are zoot-suiting up or getting Andrews Sisters’ updos. But dance schools across the U.S. are being mobbed by amateur hoofers eager to learn such trademark moves as Fall Off the Log or the Shorty George. At the Sandra Cameron Dance Center in Manhattan, the Friday-night practice sessions draw close to 100 people, crammed into one small studio. ”When I first started here five years ago, I was the youngest person. Now I’m one of the oldest,” says Angie Whitworth, 32, who helps run the center’s twentysomething-dominated swing program. And, proving necessity is the mother of invention, six students at the University of Arizona started swing dancing in their dorm last year. ”In April, we officially became a club. Now we have 250 members,” says Skyler Rodolph, 19, head of the Arizona Swing Cats.

”Big band is an up thing. It’s a couple’s thing. Grandmas and kids can get into it,” says ex-Stray Cat Brian Setzer, who went swing in ’92 and now has a radio hit with ”Jump, Jive an’ Wail.” ”This is the most awesome thing I’ve ever been in front of.”

On a small scale, the swing revival first started jumping back in 1989 in local clubs in San Francisco and L.A. Swingers gave the trend its first big exposure at the box office in 1996. The return of the cocktail culture helped too. Nothing, however, matches the influence of that high-flying Gap khaki ad that debuted last April. Set to the tune of Louis Prima’s original ”Jump, Jive an’ Wail,” the commercial was returned to the air in August because the company got so many responses from customers who missed seeing it. ”The ad put [the swing craze] over the top. It’s only been in the last five months that it’s really gone wild,” says Diane Lachtrupp, co-owner of New York’s Stepping Out dance studio, who points out that the dancing featured in the ad is the energetic Lindy Hop, also known as the East Coast swing. (Not to be confused with its sultrier cousin, the West Coast swing.)