When Serge Dorny arrived in France pledging to take opera to the masses, he didn’t expect to find them camped on his doorstep.

In fact, the incoming director general of Opéra de Lyon had to run the gauntlet of his new target audience — a gang of disaffected street dancers occupying the portico — before he could even get to his desk.

To Dorny it was too good an opportunity to miss. “I didn’t want to chase these guys out because I liked the energy they brought to the place,” says the Belgian former artistic director of the London Philharmonic Orchestra. “But I wanted to recover the space to open up a summer café — so I went to the pub with them to discuss it.”

Over beers in the city’s banlieues, the young street dancers explained that the smooth marble flooring of the peristyle surrounding the opera house was perfect for breakdancing. “Their ambition was to train for competitions — ‘battles’ as they call them. So I suggested that they come inside the building and gave them a carte blanche to work there.”

Four years later Dorny has his café, the breakdancers — known collectively as the Pockemon Crew — have become world champions, and that first dangerous act of trust has spawned one of Edinburgh International Festival’s most invigorating cocktails, a show entitled The Seven Deadly Sins infused with a heady dose of hip-hop.

The 1933 sung ballet, the last of many collaborations between composer Kurt Weill and writer Bertolt Brecht, dramatises a journey through the seamier side of seven American cities by two twin sisters — often interpreted as facets of the same personality — struggling to pay for their family home.

Directed by Canadian film-maker François Girard, the new production expands that dichotomy still further: while Anna I is played by a professional soprano, Anna II is represented by seven dancers in bright orange wigs — drawn from both classical and hip hop cultures. Meanwhile male breakdancers cavort as suited city brokers.

The show’s slick fusion of radically different worlds masks a three-year process of trust-building at the opera house. Initially escorted round the impressive modern interior by wary staff, the street dancers vindicated their unorthodox summer sojourn in 2003 by winning first the French and then the world breakdancing championships.

By the time it came to begin casting The Seven Deadly Sins, choreographer Marie Chouinard had the new recruits squarely in the frame. Nevertheless, assimmilating breakdancers and classical dancers into the same piece was a challenge. Chouinard, an award-winning choreographer and performer, worked hard to weave each dancer’s strengths into the final show.

“I started from the dancer’s quality,” she explains. “A dancer from the hip-hop world would show me pops and boogaloos and the smurf and all that. But I did not ask the girl who does hip-hop to do ballet — and I did not ask the girl who does ballet to do hip-hop.”

It’s a pragmatic approach that has reaped rewards for both sides. “They have been very patient with us,” says Riyad Fghani, the leader of Pockemon. Now taking dance workshops out into Lyon's sizeable hip-hop community, he’s spreading the word that, far from rich prima donnas, the dancers at the opera house are among their greatest allies. “They are good people and Pockemon is happy to work with them,” he says. “Serge has become a friend.”

In Edinburgh, the hope is that the involvement of two very different strands of dance will further blur the boundaries between high art and street art. In a long-anticipated double bill The Seven Deadly Sins and another short opera by the same writers, The Lindbergh Flight, will critique modern culture on twin fronts. Both target the darker side of capitalism and the result is as much dance musical as opera.

After rave reviews of the production’s recent opening in Lyon, there are already plans to draft in 20 hip-hop dancers for a production of Porgy and Bess. Dorny believes the company must be doing something right. “Today 22% of our audience is younger than 25 years old,” he reports. “We’ve created a wider image to show different generations and cultures that opera has energies to share. It’s encouraging to see that we are not building a mausoleum.”

The Lindbergh Flight and The Seven Deadly Sins runs from Mon 14 - Wed 16 August, 7.15pm, Edinburgh Festival Theatre. Tickets from Hub Tickets, 0131 473 2000, or online at www.eif.co.uk.

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