Dame Kiri Te Kanawa is a small but forceful bundle of charisma. I expect her to be a diva, of course, and there is an element of imperiousness in her bearing, but there is an earthiness, too, and she has a joyously pragmatic attitude to her industry.
"Some people say: 'Oh, I think I am going to try singing now.' I think, don't even bother. Don't even start."
This comment is surprising given that Te Kanawa is patron of the BBC Cardiff Singer of the World competition, Britain's biggest singing contest and an important stepping stone for many international stars (previous winners include Finnish soprano Karita Mattila).
Yet Te Kanawa is not, I think, advocating cruelty, but realism. In any case, the Cardiff contestants have already been heard by several expert singers. It's not as if they are walking on to a stage for the first time a la Britain's Got Talent.
She shudders at the very idea. "This is not a gladiatorial contest. I'm not sure what a TV talent show for opera would achieve. It's a tough enough profession without having someone like me being mean to them. I would not like to see a bunch of singers shouting at each other. Sometimes there is rivalry among our competitors at Cardiff, but often there isn't and it's never a competition of egos."
Te Kanawa believes that today's opera singers are more nurtured, but also that they have it tougher in many ways. "There are more pressures and less opportunities. More is demanded of them and there is more they have to conform to.
"There's more to it than simply getting up and having to sing. They are given opera after opera to study, recital after recital - it's a big workload. I was able to do things more gradually."
At a glance, however, it looks as if Te Kanawa's fame was acquired very quickly. She arrived in London to train in 1966 - "I came, I saw, I conquered" - and within four years had appeared at Covent Garden. Yet, she had already achieved a certain fame as a singer in New Zealand, where she had been encouraged by her adoptive parents and by the nuns at her convent.
At the time she was untrained and made a brief and unsuccessful foray into acting in a film called Runaway Killer about a psychopath who is described on the poster as "a young man in a hungry hurry".
Te Kanawa laughs at the memory. "Oh goodness, that was so long ago and I didn't really know what I was doing. It was just a silly thing."
Acting for her, nevertheless, has retained a residual appeal and her rare gift of combining technical ability with gut-ripping emotion has always hinted that she could have been a great classical actress. Would she have liked to play the great Shakespearean roles? "Of course!" she says, sounding slightly indignant. "What else is there?"
She says she was too preoccupied with the stuff of life to give much thought to acting back then, too busy going from one role to the next - the Countess, the Marschallin, Mimi, Arabella. Indeed there is a breezy professionalism to Te Kanawa and only now, she says, does she realise she was never properly guided, and she is determined to do better by her Cardiff Singer proteges.
"I was never nurtured. I remember my friend [American mezzo-soprano] Frederica von Stade saying to me: 'You and me, we were just thrown into the bullring.' And she was right. We just had to survive."
Part of Te Kanawa's survival technique was to analyse her strengths scrupulously. "I would like to have been a spinto, rather than a lyric soprano, but I had to settle for what I had and I never tried to take on roles that I knew I couldn't do."
This included Wagner. It never suited her, she says, and she found it hard to push against the strings which followed an aria.
There have been many highlights in her career. In 1981, she sang Handel's Let the Bright Seraphim at the wedding of Prince Charles and Lady Diana Spencer at St Paul's Cathedral and was seen by 600 million people worldwide. I ask whether an opera singer would be granted the same platform today. "Well, at Prince William's wedding everyone was asking where the wedding singer was. I felt it needed some sort of spark."
Te Kanawa has achieved a level of fame that is rare for most classical musicians. She is aware of her privileged position and, at the age of 73, retains an air of toughness you often find with people at the top of their profession. Certainly she has had to be tough. She has worked with some hard taskmasters, including Sir George Solti, Herbert von Karajan and Leonard Bernstein, who, during the notorious Deutsche Grammophon re-recording of West Side Story in 1984, constantly tore Jose Carreras to shreds for failing to master the complex rhythms.
"Oh," winces Te Kanawa at the memory. "There he was [Bernstein] with this glass of water that was actually vodka. But, you know, he was a brilliant man and when you're dealing with brilliance you've got to cope with brilliance. He was incredibly demanding but I didn't mind because he helped me achieve things that I'd never done before. I realised that he'd made my voice sustain a note much longer than I thought I could."
Today, Te Kanawa lives in Sussex (she has two children with her former husband, Desmond Park) and dedicates much of her time to her foundation, which provides financial and mentoring support for singers from New Zealand. It's a force for social good and a sign that Te Kanawa has not forgotten where she came from.
"If you know where I started, you'll know that I'm really not posh," she says. "I've played many queens in my life, but really I was living out a fantasy." And for a split second, this no-nonsense diva looks rather nostalgic. Telegraph Group Ltd