WHEN IT CAME down to either trying out for the Sydney Olympic Games or performing with Cirque du Soleil, British gymnastic champions Kevin and Andrew Atherton made the only choice they could: They ran away and joined the circus.

The identical twin brothers knew they wanted to be part of Cirque du Soleil the first time they saw the company perform at London's Royal Albert Hall.

"It literally gave us chills," says Andrew, who is the older twin by three minutes. "The high level of athleticism, the performance, we'd never seen anything like it before."

The Athertons are touring with "Varekai," Cirque du Soleil's latest production, which rolls into town this week, hoisting its big top on the grounds of RFK Stadium.

For the past 20 years, Cirque du Soleil has combined athleticism with artistry -- each performance a mix of drama, acrobatics, choreography, innovative sets and world music -- to reinvent the meaning of the word "circus." "Varekai" ( translated as "wherever" from the Romany language of Gypsies) is Cirque's newest production and pays homage to the nomadic spirit and art of the circus.

Viewers of the Bravo reality series "The Fire Within," which chronicled the development of "Varekai," will remember Kevin and Andrew. The muscular blond duo were featured each week, working hard on creating a bold and innovative new aerial act.

The result is a breathtaking two-man strap act; the brothers hang from a leather strap, about the width of a seat belt, soaring and performing synchronized acrobatic moves 60 feet above the audience, all without a safety net or cables.

"I've got to place 100 percent trust in my brother," Andrew explains. "I am holding on to the strap; Kevin is attached only by holding on to me. At one point, I've got the strap with one arm, Kevin with the other, and the only thing that is keeping me on the strap, keeping me from falling, is the weight of my brother pushing down the back of my hand. People always say that they can't believe what they're seeing."

A two-man strap act is fairly unusual, Kevin says. Traditionally, a strap act is performed solo. Here, at Cirque, the brothers Atherton each fly on their own strap, then combine to one, melding midair to perform precise and powerful movements high above the audience.

"Strap acts are usually done with only one person, and the toes are kept pointed to make clean straight lines," Kevin says. "We broke with that, combined hip-hop and fast movements, flexing our feet, breaking the line and making shapes with our bodies. With two people, it has a completely modern and unique feel."

The Athertons' role in "Varekai" is part of a dream sequence; the main character, an Icarus figure, has fallen from the sky and dreams of once again taking flight. Audience members have described the brothers, in their close-fitting black costumes and headgear, as "black birds," calling their aerial performance, with its intricate and mirror-image maneuvers, "birds in flight."

Andrew says people often come to him after the show to tell him that their act gave them chills. Both Andrew and Kevin are quite familiar with this feeling. "We absolutely get chills every night when we perform; even though we created the movements, it still gets to us."

Audience members sometimes describe Cirque du Soleil's aerial strap artists, Kevin and Andrew Atherton, as "birds in flight."