It is the perfect grand opera story. A superstar tenor sings underwhelmingly at the world's most exacting opera house and storms off stage with a shake of the fist amid a torrent of booing. An understudy in jeans is thrown on in his place and has a night of triumph. Roberto Alagna's walkout from La Scala's season-opening Franco Zeffirelli production of Verdi's Aida is an opera story with everything - and with the bonus that it confirms all our prejudices about the art form, too.
As it happens, many of the world's greatest opera singers, past and present, are remarkably normal, nice people. You will wait a lifetime to hear stories of Renée Fleming flouncing around, Bryn Terfel throwing a tantrum, or Placido Domingo storming off the stage. Though they are at the pinnacle of the operatic world, they just don't behave that way. One of the indisputably greatest sopranos of the 20th century, Joan Sutherland, was famous for getting on with her knitting when she wasn't needed.
But the world prefers its opera stars to be divine monsters. And opera's so-called "golden couple", Alagna and his wife Angela Gheorghiu, have become increasingly willing to oblige. Management are driven mad by the demands of the Burton and Taylor of the operatic world, but they know the duo are a bonanza at the box office. Both sides ramp up the process: the top houses compete furiously for the stars' services; the stars become ever more outrageous in their behaviour. And so it goes on, until something snaps.
Which occasionally it does. Alagna's walkout on Sunday was denounced by La Scala's artistic director, Stephane Lissner, as a "blatant lack of respect for the audience and the theatre", and Alagna was substituted in last night's third performance of the run by Walter Fraccato rather than Antonello Palombi, whose heroics on Sunday won him a nine-minute ovation from the Scala audience. But Alagna has said he will be back for tomorrow's performance. "Roberto Alagna ritorna vincitor," he announced yesterday, quoting the famous line "Return as a victor" from Aida itself. The stage is now set for an epic confrontation with Lissner. Will tenor power prevail? Or will Alagna be sent packing?
The careers of both Alagna and Gheorghiu rocketed a decade ago. He looked like the hottest young tenor around, the destined successor to the Pavarotti-Domingo-Carreras generation, and was duly dubbed "the fourth tenor". She took the operatic world by storm in La Traviata under the late Georg Solti at Covent Garden in 1994, and seemed to be the lyric soprano the world had been waiting for since Sutherland's retirement. When the two married, they became the darlings of the opera houses, the record companies, opera-goers and the accountants.
But they were rarely the darlings of the directors - Jonathan Miller once dubbed them the Bonnie and Clyde of opera. Alagna was respected early on for his fine singing in the French repertoire, but his attempts to make himself the dominant Italian tenor of the era proved more difficult. Gheorghiu's career began to overtake his in the late 1990s, as she added more punishing roles - Nedda in I Pagliacci and Tosca - to her repertoire. But neither of them has disarmed the critics in the same way they have captured the public imagination. When Gheorghiu sang Tosca at Covent Garden for the first time this summer, the Guardian's Tom Service thought her acting underplayed and her singing underpowered.
Alagna's walkout from La Scala comes at a time when a lot of the glister has gone from the one-time golden couple. The previous Scala regime under Riccardo Muti fell out with Gheorghiu as early as 1997. The New York Met's recently retired general director, Joe Volpe, had a bust-up with her. Now it seems the soprano has fallen out with Covent Garden. Rumours that she was dropped from a forthcoming production of Verdi's Don Carlos - because music director Antonio Pappano was so angered by her failure to turn up for rehearsals at this year's Tosca that he has declined to work with her again - have been flatly denied. Covent Garden insist Gheorghiu decided to withdraw. "She wasn't quite sure that it was a role for her ... and she was slightly uncomfortable with it," said a spokesperson. Either way, the doors of the big houses are being bolted one by one.
Opera history is crammed with monstrous behaviour by publicly adored singers. A century ago, prima donnas with every bit of Gheorghiu's hauteur - and more talent - behaved in a tyrannical manner that she can only dream of, Nellie Melba being one of the leading examples. Callas's angry temperament was legendary. The record producer Walter Legge, a man used to getting his way, called her "vengeful, vindictive and malicious" - and Callas was not above violence against managers who criticised her.
In the generation before Alagna and Gheorghiu, opera divas such as Jessye Norman and Monserrat Caballé were notorious for the demands written into their contracts (Norman even specified the make of Rolls-Royce in which she was to be collected from the airport), and for the disdain they showed directors. More recently, Cecilia Bartoli has carried on the tradition.
Opera houses usually try to stop stories of demanding behaviour getting into the press. But the veil was lifted when Volpe fired the soprano Kathleen Battle from the Met in 1994, publicly citing her "unprofessional actions". Battle stories are legion - such as the one in which she rang the Boston Symphony Orchestra management to complain that the Ritz-Carlton had put peas in her pasta, or the occasion she phoned her management in New York from a limousine in California to instruct them to call the chauffeur to turn down the car's air-conditioning. After one show at the Met, the soprano Carol Vaness told Battle as they took their bows that, on behalf of everyone else in the show, she hoped they would never work with her again. When Volpe announced that he was firing Battle, the cast cheered and applauded. Battle's manager reminded Volpe that his predecessor was always known as the man who had fired Callas from the Met. Do you want to be known as the man who fired Battle, he demanded? Volpe had the perfect reply: "Kathy Battle is no Maria Callas."
In the end, that's what it comes down to. If the singer is truly great, then most managements will put up with anything. If they're not, there comes a time when even the most income- and celebrity-conscious management decides to let the diva hang. There may be fewer great singers than ever around these days, but have Alagna and Gheorghiu had a tantrum too far?