Preview: Don Carlos, Royal Opera House, London

The stand-in takes over on centre stage

Cast changes due to illness are normally greeted by groans, but not when it was announced at the last minute that Ferruccio Furlanetto would stand in as Fiesco in the Royal Opera's Simon Boccanegra last month: some critics meanly wished the sick absentee a long, slow recovery. Furlanetto's deep bass warmth seemed to pervade the stage even when he wasn't singing, and his unique sound gave that tempestuous opera a rock-solid foundation.

The reason why he happened to be on hand will be apparent when the curtain rises tomorrow on Nicholas Hytner's eagerly-awaited production of Verdi's Don Carlos, where he'll sing the part of King Philip – the musical and emotional complexities of this role require singing of supreme accomplishment.

To meet Furlanetto is to encounter that same extraordinary warmth in close-up. Clean-cut and handsome, he radiates regal repose, and his thoughts flow with such smooth unstoppableness that it's hard to get one's questions in.

What did he feel when he got that frantic summons? "It was a role I had done many times and love very much, and sometimes I like to jump into things at the last moment. If you have a month of rehearsals, it can get a bit over-cooked. Jumping in, you are fresh."

He was once jumped by Herbert von Karajan into the King Philip role, with life-changing results: "Before that, I was just a promising young bass, but the day after I was somebody – that was the effect Karajan had on people's careers.'

Since then he has had, he smilingly concedes, a satisfyingly smooth career: after a busy few years learning the main roles in provincial Italian opera-houses, he went into international orbit and stayed there.

But there's interesting prehistory: as a teenager he had his own pop group, and specialised – thanks to the timbre of his voice – in the Tom Jones repertoire. Before that, he was singing arias for his opera-mad great-grandfather when he was seven. "I never had a 'white' voice," he says. "It was a light tenor, and when you are born with a gift like that, you sing all the time. I always felt a responsibility towards my voice."

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