Katherine the great: Katherine Jenkins

Last week, it was announced that Katherine Jenkins had signed the most lucrative recording contract in the history of classical music.Not bad for a no-nonsense choir girl from Neath. John Walsh meets the $10m woman, Portrait by Dan Burn-Forti

(Dan Burn-Forti)

Katherine Jenkins is so pretty, so cute, so wholesome and so winning, it's hardly surprising some people can't stand her.

You just don't get this level of sexy innocence every day. You do not encounter this head-on collision between Marilyn Monroe and Rebecca-from-Sunnybrook-Farm very often in the serious world of classical music. But then the music world isn't sure just how seriously to take Ms Jenkins. She brings a voice of exceptional purity to the singing of hymns and light classical tunes, but neither she nor her record company will call her an opera singer.

Nor will music critics. Tim Ashley of The Guardian wrote, "She can't really be called a classical singer." Norman Lebrecht of the London Evening Standard complained that she'd "never sung in an opera house." David Mellor wrote in the Mail on Sunday, about her performance of Holst's "Jupiter", "The great soprano Elisabeth Schwarzkopf once coined a word that sums up perfectly the sheer awfulness of this bathetic rubbish: vomitacious." And the online opera gossip website Opera Chic is always harping on about her "bewbs", calling her a "pOperaTart" and complaining that she hasn't a trained singing voice. Meanwhile, the red-top newspapers, never averse to statuesque pretty girls singing in frocks, faithfully record her overseas trips to entertain British soldiers in Iraq and Afghanistan as though she were already a 21st-century national sweetheart, like Vera Lynn; but they also greet any chance to snap Ms J in her abyss-like décolletage.

Fans and foes alike have had much to chew on recently. At 28, she's just released her sixth studio album, Sacred Arias, a collection of familiar hymns and hymn-like songs, from "Abide With Me" to Leonard Cohen's "Hallelujah". The CD sleeve reveals Ms Jenkins at her most sexy-vestal-virgin, posing in frothy net or sleek satin gowns, posing saucily in a tight white frock behind an immaculate white curtain. Its release coincides with a raunchy photo-shoot in GQ magazine, in which Katherine's curvaceous frame is poured into some tight, black strapless numbers, and black suspenders clutch her thighs. Across the nation you can hear strong men groan at the madonna/whore conflict Ms Jenkins engenders in their hearts.

If that weren't enough, it was announced last week that she's struck professional gold. She's just come to the end of her six-album contract with Universal Classics and Jazz, which netted her £1m in 2003. After long negotiations, she's been signed by Warner Music for a five-album deal that will bring her $10m (£5.8m) and is, according to industry insiders, the biggest classical recording deal in history. It's her big chance to break into the lucrative American market. Her success hasn't gone down well with everyone. "Katherine Jenkins to Gain $10m by Watering Down Classical Music and Singing Into Microphones," sneered the Opera Chic headline. Microphones, indeed. How gross.

We meet at the Electric Cinema in west London's groovy Portobello Road. Ms Jenkins is all teeth, smile and tons of eye-liner. Her dyed-blonde hair is tousled as if she's been recently roused from an afternoon lie-down. She's looking very late-summery in a belted grass-green dress, in which an inch of bra-cup has become exposed. It's an attractive package that drives the first few questions out of your head. But Ms Jenkins is straight-talking and friendly, and laughs at male confusion.

Was the timing coincidental, I ask, to present the sacred arias and the hot bod simultaneously, to show there are two sides to the Welsh diva? "I've never done anything like this before," she says, widening her huge blue eyes. "I've been approached to do shoots, but never by GQ. And the timing fitted in with the album. But it's really a fluke." Which other magazines asked her? "Oh, you know – the other kind," says Ms Jenkins disapprovingly. "Bikini shoots for FHM and Loaded. But I never wanted to do that. When GQ offered, I thought it would be interesting to work with the creative director, who was from Vogue."

Yeah, or so he said ... "When I got there, there was a huge selection of, er, undergarments, things like that. Some of them were a definite no, absolutely not. But as the day went on, I got a little more relaxed." She asked for picture-choice approval, and called in family advice. "They respected that I didn't want to go too sexy with it. I showed the pictures to my Mum. She said, 'Well, I suppose we could see more of you on a beach.' So that was OK."

Is this the beginning of a new Katherine? Is she going to raunch up her image, like Kylie and Charlotte Church? She gives me a pitying look. "I'm sorry," she says, "but that's as raunchy as it gets."

For someone who has done so much in five years – four classical No 1 albums, four million record sales and the distinction of being the first classical artist to have two No 1 albums in the same year. She exudes a breathy, down-home excitement about recording, choral singing and the challenge of transmitting the classics in a war zone to large numbers of military chaps with more earthy matters on their minds.

The new album finds her surrounded by orchestras, choirs and choruses, above which the Jenkins mezzo-soprano floats serenely. If her voice is, like Charlotte Church's, the "voice of an angel", hers is seraphic while Church's is merely cherubic. Her delivery is pure and straight, but there are moments when you can detect a tiny kick of the vocal heels, as if she were keen to rock things up. You can hear it at the end of "Abide With Me" and the climax of "Down In the River to Pray" ("Let's go down, won'tcha come on down ..."). Does she feel she wanted to show off a little more?

"With songs that have been done a million times, it's nice to do something slightly different," she says. "And 'Abide With Me' has been done so many times. I was asked to sing it at the FA Cup final this year, and they all sang along. It was pretty huge." Would she sing it to the troops in war zones? She gives me an Oh-please look. "I don't think I'd sing that. When I sing to the troops, I have to think, 'How would this music be welcomed by four thousand squaddies?' The first time I went to Iraq, I sang 'Nessun Dorma', because they'd be familiar with it from the football, and 'Silent Night', which went down well. Then I did 'Somewhere Over the Rainbow' but I wasn't sure if they'd like it. And the men all sang along with the chorus. I got a real lump in my throat because they were away from their families and Christmas was coming ..."

Her favourite track on the new album, she says, is Cohen's "Hallelujah". "I love that piece," she says. "It makes me cry." So why did she leave out the second verse? "Did we?" she asks. Yes you did, I say, the verse with the lines, "You saw her bathing on the roof ... She tied you to a kitchen chair / And broke your throne and cut your hair." Why edit that out? "Yes, well we did have to look at the lyrics," she says briskly, suddenly a frontier-town schoolmarm. "Because it's not strictly a religious song, is it? And we changed one line as well." The line in question is, "I remember when I moved in you," which has been altered to: "I remember when I moved with you." It seems a shame to take an image of sexual connection, and change it to read as though the singer was moving house to Croydon. "It's a beautiful song but it had to be adapted," she says firmly.

She recorded Sacred Arias at Air Studios in London, which is, appropriately for the record, a converted church. "I didn't realise it had been a church until we were doing 'Abide With Me'. I was so pleased because I started singing in church. From the age of seven until I came to London at 17, I sang at two services a week, and at least two choir practices a week. I don't think I'd be here without my church."

The church was St David's in Neath, where she grew up in a devout Church of Wales household. Her mother was a mammographer, her father a retired factory worker. Neither had the least interest in classical music. "My dad liked Shirley Bassey. He would sing but in a crooner style, like Matt Monro. My mum liked Tom Jones and Tina Turner. They played a lot of Doris Day, and I know every word to all her songs." She did a belting version of "Whipcrack Away" – the eternal tomboy's classic from Annie Get Your Gun – in Viva La Diva, her song-and-dance extravaganza with Darcey Bussell which started life in Manchester last November.

The young Katherine was never short of ambition. She started singing at four, when she entered her infant school talent show. "I came back from school and said to my Mum, 'I don't have any songs to sing.' So she taught me one, and got me singing it on video and now she shows it to everyone." What's it called? She smiles. "It's called 'Going Down the Garden to Eat Worms.' Do you know it?"

I say I don't think so. Is it by Leonard Cohen? She gives me a look, and proceeds to sing her début number, with all the actions:

"Nobody likes me,

Everybody hates me,

Going down the garden to eat worms.

Big ones, small ones,

Fat ones, thin ones

See how they wriggle and squirm.

You just [she gnashes her perfect white teeth] bite off their heads

And [she makes a lovely "O" with her mouth] suck up the juice,

And throw the skins away,

Nobody knows how I survive

On worms three times a day."

She sits back, daring you to find her anything but adorable. Was that really, I ask, the song that started her off? "They laughed," she says. "And that was it. I knew then what I wanted to do."

She joined the church choir at seven. By nine, she was head choirgirl. It's scary to think what reign of terror and intimidation the midget Jenkins inflicted on her tiny co-choristers. "I didn't wonder whether I had a good voice or not. I just loved singing. Then, when I was 10, someone recommended I enter the Choirgirl of the Year competition, a few other kids in school entered it too. I sent off some tapes, and got in and I won. It was the first time I thought, maybe I could do something with this."

There followed the punishing regimen of choir practice, piano lessons and church service. "Church and religion were very important in our family. But I have had times in my life when I've lost my faith a little." Such as when? "Such as when I lost my Dad." Selwyn Jenkins had his two daughters comparatively late in life and died of cancer, aged 70, when Katherine was 15. It was obviously a shocking blow to her. "I didn't really understand why this was happening to us. I didn't think it was fair. I didn't think it was fitting." Her voice takes on a sudden steely tone. You can imagine Almighty God feeling a little chastened.

It occurs to me that every other little girl growing up in the late 1980s would have been a fan of Madonna. Had "Like a Virgin" and "Like a Prayer" bypassed the young Katherine completely? "I loved Madonna," she says with feeling. "The very first song I owned was 'Material Girl'. But a lot of that was to do with the glamorous video, because she dressed like Marilyn Monroe who was my idol – pink dress and gloves and diamonds. It captured my imagination." She wrinkles her brow. "I think I was a bit too young to think about the lyrics."

Could she ever have taken a sudden turning off the classical-hymnal route and become a pop singer? She looks pained at the thought. "There were moments when I liked a couple of bands I shouldn't admit to – like New Kids on the Block – but I was never a hard-core fan of anyone. I went to school, and after school I had piano or singing lessons. I got a scholarship to the Royal Academy of Music when I was 17 and went there at 18." So if she were given a one-hour slot on Radio 2, to present her favourite records, how many would be, you know, Motorhead and AC/DC?

She laughs. "I put all my favourites into Viva la Diva – Callas and Streisand and Piaf and Doris Day and Judy Garland singing 'The Man That Got Away'."

Try as you might, you'll never steer Ms Jenkins away from the classical-crossover niche in which she's embedded herself. She won't be turning herself into Charlotte Church any time soon. The immediate plan, now she's got the jackpot $10m deal, is to break the US. "I'm going there next year, to make an album. It's such a massive place, you have to go and put the time in." She's moving to Los Angeles, and will be working with Placido Domingo and David Foster, the producer of Michael Bublé. Is she targeting the Bible belt, as natural consumers of her stuff? "No, I wasn't intending to make a religious album," she says. "I don't want to come across as overly religious."

Whaaaat? It's a frustrating business, talking to Katherine Jenkins about what she does or what she might become. She's a lovely singer stuck in tight, sparkly evening dresses (she's the worldwide face of Mont Blanc jewellery) and a vanilla-flavoured light-classical world. She's too young and foxy to be the nation's sweetheart that she's turned into. She's a shrewd businesswoman (with rumoured earnings of £9m already) who talks as though she's still in the school chorus. She's an old-fashioned girl who has just signed a deal for an old-fashioned ten million dollars. If that's the price of not raunching it up, who's to argue with her?

'Sacred Arias' is out now on Universal