Mark Ravenhill and Michael Nyman - Take your seats for jazzed-up Monteverdi

On the surface they don't have much in common: Michael Nyman, composer of the "killingly popular" – his words – soundtrack to The Piano, grandee of the UK music world now trying to get his operas onto serious UK stages, and Mark Ravenhill, risqué playwright who brought Shopping and Fucking to our stages in 1996 and has continued to challenge audiences' tolerance levels ever since. But Monteverdi's Coronation of Poppea has unleashed in the two artists a rather extraordinary new venture that, if cared for properly, could fuel a surge in opera-going, and opera-writing, that could be very exciting.

The first fruits of this partnership can be seen on the stage of Islington's Kings Head Theatre next week: a new production of Claudio Monteverdi's 17th-century opera The Coronation of Poppea – one of the first operas ever written – that has been translated into English by Ravenhill and contains a new aria by Nyman. It will be performed by the young and dazzling – and Olivier-award-winning – OperaUpClose ensemble.

"The question I've always asked myself about Poppea," says Nyman, is whether Monteverdi knew that his final love duet, 'Pur ti miro', which is one of the most beautiful pieces of operatic music ever written, was a killer hit. I always wonder whether Monteverdi knew how right he had got it."

Eighteen years ago, Nyman wrote a piece of music that has now sold in the region of three million copies – the soundtrack to Jane Campion's Oscar-winning The Piano. It was a theme entitled "The Heart Asks Pleasure First", specifically, that took off. The composer had no idea what he'd come up with.

"I was under huge pressure to provide Holly Hunter with six or eight piano pieces that she had to learn before they went on set – for her to play on location. Basically, I had a number of cues – 'Cue 1, Cue 2, Cue 3' – that I just had to get through; I finished one, ticked it off, went to the next one, 'The Heart Asks Pleasure First', I think, was called 'Cue 2', and I just found a Scottish popular song – 'Gloomy Winter's Noo Awa'' – and I made a version of it that I thought a well-brought up woman pianist in the 1850s might have played if she'd known a little bit about minimalism – so I was writing her character through my own music – filtered through the music of the mid- 19th century. And then suddenly the film takes off, particularly that theme. I was totally unaware of the effectiveness of my own most famous piece of music until people started responding to it. It's why I always wonder whether Monteverdi knew with 'Pur ti miro'."

Nyman's obsession with this single blissful duet – Spotify it if you don't have a copy of Poppea to hand, it is the most utterly transporting piece of music, and declaration of love, you will ever hear – led to the invitation, by Ravenhill, for Nyman to write a new "intervention" aria that would precede it. He wasn't just giving Nyman a bit of pleasure, he was troubled by the distance in knowledge between today's audience and the Venetian audience of the mid-1600s.

"The original audience would have been much more aware of the irony of 'Pur ti miro'" Ravenhill explains. "They wouldn't swoon in the way we do today, they would have been laughing. They knew their sources of this opera, Tacitus's Annals – they would have known that the relationship between the young emperor Nero and his mistress Poppea would have lasted only about a year; that Poppea would be kicked by Nero during pregnancy, losing her own and the child's life; that Poppea would send a messenger to Nero's exiled wife, Ottavia, ordering her to kill herself, and for her head to be delivered back to her as proof etc. I wanted the contemporary audience to be in the same position that the 17th-century audience, with their classical Renaissance education, were in."

Ravenhill went back to Tacitus for his new aria, the very text that Venetian librettist Busonello – then billed higher than Monteverdi – would have consulted when he wrote his libretto. Ravenhill has spent six months writing this new translation of the opera, which will be accompanied by a jazz ensemble led by musical director Alex Silverman: sax, double bass and piano replacing the "four undefined instruments" dictated in Monteverdi's score.

The new aria is written for Ottavia who, here, comes back, spirit-like, to warn Poppea of what's ahead.

"I wrote the words with the Nyman sound in mind – I wanted something that would jar with the rest, not a Monteverdi pastiche – so I was writing for Nyman's very definite pulse, his persistent beat. I wrote something with a very strict metre and pared it back and back and back so it's very spare – it's much sparer than the rest of the opera. The idea is that Poppea goes into 'Pur ti miro' with the knowledge of the future."

With the exception of the Nyman intervention – which, ironically, does have a sense of Monteverdi about it in its overlapping – musically, The Coronation of Poppea will sound instantly recognisable to audiences familiar with the original; it's the same melodies and structures, just delivered on different instruments and improvised with a little differently. "It's a bit shorter, too" adds Ravenhill, "I've cut about an hour off it; and tried to make the language more the way we speak today".

At its core, The Coronation of Poppea is a very modern opera; Ravenhill didn't have to change much. "It's much more modern than Handel, even Mozart. It's more in the spirit of the writing of Berg's Lulu," Ravenhill offers. "The recitative is always moving, there's no stand-and-deliver moments that we traditionally associate with opera. And it's a domestic drama – it's about two people who were infatuated by each other. Two people whose lives have gone down in history".

It is also, perfectly for Mark Ravenhill, all about sexual and gender ambiguity, if understated. "Yes, it is very me, isn't it! In recent productions, the parts of Nero and Poppea are both played by women – Monteverdi wrote Nero for a male castrati – but I've chosen to lose the moustache and male disguise that most directors opt for and go for a more androgynous, Annie Lennox-type Nero instead." Having already seen some of the exquisitely intimate scenes – a touch uncomfortable – between the two lovers, the relationship, in Ravenhill's hands, becomes moving rather than ridiculous, as is often the case on experiencing a woman and a woman dressed as a man rolling around the stage.

There is a chance that this drama of epic lives could get a whole new audience now that new writers and performers have got their hands on it. It is what OperaUpClose is about, bringing Butterfly, Bohème, Pinafore, Pagliacci down to a new level – one that makes sense to an audience living several hundred years after these productions were written. So that does mean an orchestra gets replaced by a sax and a piano, and Mimi does first chance on her Ronaldo having run out of money for a parking meter.

'The Coronation of Poppea', Kings Head Theatre, London N1 (020-7226 0364; www. kingsheadtheatre.org) to 19 May