Eyewitness account

The Franco-Italian singer, who was playing a leading role in Verdi's Aida, walked off minutes into the second night of the opera house's new season.

His understudy rushed on wearing jeans and carried on Sunday's performance.

Alagna blamed a hostile audience for his exit. The conductor said he had never seen a singer walk off before.

The production's opening night on Thursday had been keenly awaited, with many hoping it would re-establish Italy's place in world opera.

The VIP-studded audience - which included Italian Prime Minister Romano Prodi and German Chancellor Angela Merkel - applauded for more than 15 minutes after the final curtain.

'Nervous start'

But the reviews of Alagna - playing Radames, the Egyptian commander who must choose between his love for the slave Aida and his loyalty to the Pharaoh - were not all complimentary.

In front of this evening's audience, I felt like I was in a different world Roberto Alagna In pictures: Opening night

And the second performance got off to a poor start for the singer, who made a "nervous start", according to Italian newspaper La Repubblica.

When his rendition of the aria Celeste Aida was greeted by boos and whistles, Alagna stopped singing and walked off stage, leaving his partner in the duet stranded.

Understudy Antonello Palombi hurried on a few moments later, dressed in jeans rather than a costume and without a proper vocal warm-up, to carry on the show.

"They literally took me and threw me on stage," he told Italian news agency Ansa after the show. "It was a good test and I passed it."

The management apologised to the audience - which is known for being demanding at La Scala - before the third act began.

Speaking after the performance, conductor Riccardo Chailly said: "In many years at La Scala I have never seen anything like what happened tonight."

Alagna, who was born in France to Italian parents, told reporters later: "I have sung around the world and I've been successful, but in front of this evening's audience, I felt like I was in a different world.

"The true spirited and fiery public wasn't there."

Tickets for the show cost up to 2,000 euros (£1,352; $2,637) and all 11 performances sold out within 24 hours of going on sale.

The next performance is scheduled for Tuesday evening.