Not over till the fake ladies sing

OPERA: You thought divas were women? So did Jenny Gilbert, until she discovered La Gran Scena, New York's drag-opera troupe

It's not often one is emboldened to ask a man whether he wears frocks in private. In his pistachio wool blazer and crisp white shirt, Ira Siff displays none of the usual symptoms. But this is a man who, if he thought he could get away with it, would proudly describe his occupation on his US passport as "diva". And for the next fortnight, at the Bloomsbury Theatre, he'll be appearing as his alter ego, Vera Galupe-Borszkh, in a show that purports to give fans an operatic account of her extraordinary life, aided and abetted by the sundry other "divas" who make up La Gran Scena, the all-male company Siff directs.

It may have started 20 years ago on New York's borscht-belt comedy circuit, but this is no ordinary drag show. Nor is it a philistine parody of high art. These are professional singers; their fan base includes Joan Sutherland, the real-life retired diva. "The first time I got into a dress was the dress rehearsal for the first Gran Scena show," says Siff, "At that point I was very uncomfortable. I hated drag. When it's a question of how-do-I-look-how-do-I-look? it's just boring."

So why do it? Why dress up as Violetta and Butterfly and get under the skin of a retired soprano with a dodgy marital past and a medical history of nodules on the larynx? "This probably sounds very arch, but it's not a parody," he says, emphasising the point other interviewers may have stubbornly missed. "We do it because we love opera that much - the music, the stars, the whole scene. Opera has been like a best friend to me since I was 15 years old [Siff is now knocking 50] and it's funny," he says, "It's inherently funny, so it doesn't need to be parodied. What we do is pull out the quirks that are already there and say to the audience, 'Now it's OK to laugh. You went to Covent Garden last night and bit your lip. Now it's OK when the fat lady is supposed to be 16, when the plot is unintelligible anyway. Go ahead and giggle."

Other parodies of opera might play down to the audience with big-bosomed Valkyries and slapstick. But La Gran Scena plays it more or less straight, giving the music's original emotional signals full beam. The comedy comes in the detail. In the company's last show, which came to the Bloomsbury four years ago, a diva from opera's golden age, a very, very old lady, comes on and sings in a faded, 78-rpm kind of voice, reminiscent of Melba. She walks with a cane, and her song gets stuck like an old record. When someone thinks to move her cane, the song continues as if it were the needle. "The audience hoots. But when she reaches her finale, gets out her hankie (a five-foot Italian flag in which she drapes herself) and sings a set of variations on "Home Sweet Home" in a beautiful faraway voice, you could hear a pin drop. More than that, Siff says, he sometimes actually hears people sobbing.

The audience wasn't quite that emotional on the night I went, four years ago. But they were palpably stunned by the vocal technique of these fake prima donnas. To a man, they negotiate the manner and articulation of late-19th-century soprano arias with an accuracy and polish that strains belief. More remarkable still, a handful of them sing with a refinement of colour and tone that is meltingly gorgeous. Not one of them has had the op, they swear. When a male singer works exclusively at his "head" register, Siff explains, the agility and range of the female voice are all within reach, and there's the added bonus of power that comes from a man's larger frame. It is a matter of profound satisfaction to him that in the wider world of international opera, the falsetto voice is regaining popularity (viz, the Royal Opera's current production of Handel's Giulio Cesare, which uses three counter-tenors - in roles that were actually written for men to sing).

"Back in the Eighties, straight counter-tenors were meant to have white, vibrato-less voices, so you had people hooting like owls," says Siff. "Philip Koch, who sings in my company as Philene Wanelle, has a very beautiful voluptuous mezzo, and for years he couldn't get work. Now it's flip-flopped to the stage where in baroque opera, singers are sought for exactly the qualities he was rejected for. It's the bane of my life, actually, because it takes away my good singers all the time. But I'm also happy to see it. When I heard my first counter-tenor at the Met, there were laughs when the high voice came out a 6ft frame. Now the novelty is wearing off, and critical faculties can come into play: I don't like this one, I do like that one, as with any conventional voice type."

Partly with this in mind, La Gran Scena steers clear of baroque repertoire. "Romantic opera and verismo opera - Tosca, La Fanciulla del West, Cavalleria Rusticana - that's the meat and potatoes for us," says Siff. "The term gran scena was originally used in the last century for big scenes, written for the prima donnas, where they got to showcase their gift in the context of going mad, going mad or ... going mad. You don't write gran scenas where people were having a nice day." The new show does dip its toe into the 20th century with an extract from Manon, but only enacts the most hysterical scene, where she seduces her boyfriend out of a monastery. "There has to be overwrought stuff going on or there's no point."

The new show is what Siff calls "a book show", a musical biography of his character Vera, beginning in the wheelchair and flashing back to the cradle, taking us through her career, her marriage to a castrato ("good match for a diva, its saved a lot of time"), her farewells, her comebacks and her masterclass - including an encounter with a monstrous student, a mobile-phone-totting black soprano called Kavatina Turner.

Like everything in opera, you can't invent it, according to Siff. Divas really do talk to their agents on their mobile all the way through dinner with somebody else. They really do talk in three languages at once ("e troppo langsam, cherie"). Siff has been there, heard that, seen it all - and after 20 years of living with Vera Galupe-Borszkh (aka "La Dementia"), actually feels himself becoming distinctly more prima-donnerish with each passing year. "Imagine it! I'm at the mercy of those two little pieces of flesh on any given night, and it's a nightmare. Do they have mucus? Was there a sinus day? Is the place mouldy? Is it dry? Oh my God, should I cancel?" But that's one thing Ira, if not Vera, would never ever do.

Bloomsbury Theatre, WC1 (0171 388 8822), Wed-Sat & 21-26 Oct.