Rolando Villazón - Why variety is the spice of life for this top tenor

Barry Manilow, Pixie Lott, Peter Kay – and a top opera star? What on earth is Rolando Villazón doing in the Royal Variety Performance?

"It's fun," declares the celebrated Mexican tenor, 39. "It's different from what I normally do, but it's an opportunity for me to have a great time." His contribution to the annual bonanza of stage entertainment is not especially operatic: he sings "Smile" from the Charlie Chaplin film Modern Times (which is on his album of songs from the movies, La Strada) and "Tonight" from West Side Story. The latter is a duet with Hayley Westenra, who is better known for her appearances at rugby grounds and military occasions than for actual opera. Cue cries of horror from opera purists: oh no, Villazón is doing the dreaded "crossover" again!

Don't sniff. Villazón says it was crossover that led him to opera, rather than vice versa. He might never have started singing if, aged about 10 and growing up in the suburbs of Mexico City, had he not heard Plácido Domingo's album of "crossover" love songs. "There was nobody in my home who was close to opera or classical music," he says. "Then, by accident, I ended up with this album. I would never have put on a recording of Domingo singing classical arias, but I heard these love songs and I fell in love with his voice. I bought all the crossover albums of Domingo – I was listening to them, trying to sing like them, learning the songs. It all started there. I had a crazy dream that one day I'd sing with him – something I never expected to come true."

But come true it did. In 1999, Villazón entered Operalia, the competition for young singers that Domingo had founded; he scooped two first prizes. At the winners' concert, he and Domingo sang together: "It was absolutely amazing. Afterwards, we became good friends. He has been extremely important in my career: an inspiration, a friend and an example."

Villazón has recently made a triumphant comeback following an operation in 2009 to remove a cyst from inside one of his vocal cords. The condition could have cost him his career – indeed his voice – had the cord not healed successfully. An onslaught of criticism dogged his recovery, ready to blame his problems on singing too much, too soon. Yet the cyst had nothing to do with singing, he emphasises: it was "genetic" and could happen to anyone, singer or not.

"I was doing a lot – but am I the only one? Of course not," he insists. "There are unwritten rules in the world of opera that we should destroy. For instance, 'One has to learn to say no'. We all say no to a thousand things. One has to learn to say yes! You have to be ready to take up opportunities, because this absurd system of signing four or five years in advance means that if you don't, you could wait 10 years for another chance.

Last year, he made further waves by agreeing to be a judge on Pop Star to Operastar, where his presence appeared to give the TV talent show a credibility its critics weren't convinced it deserved. The TV world took him by surprise in many ways. "I don't watch TV," he explains. "I haven't watched TV for years. They asked me about The X Factor and I didn't know what it was. Katherine Jenkins used to laugh at me because they'd mention names of famous people and I didn't know them.

Suitably liberated, Villazón has bounced back. He has undergone the greatest danger a singer can experience and emerged stronger than ever. "It was difficult," he acknowledges. "But it was also a great time. If I had to live my career over again, I wouldn't change a thing. Not even the cyst."

'The Royal Variety Performance' is on tomorrow at 7.30pm on ITV1. 'La Strada' is out now on Decca