With her husband Elvis Costello also away, jazz singer Diana Krall s own world tour – which includes a stop-off at Kenwood on Saturday – is going to be a challenge – especially with two toddlers in tow, she tells Katie Masters Good jazz is when the

With her husband Elvis Costello also away, jazz singer Diana Krall's own world tour - which includes a stop-off at Kenwood on Saturday - is going to be a challenge - especially with two toddlers in tow, she tells Katie Masters

'Good jazz is when the leader jumps on the piano, waves his arms, and yells.

"Fine jazz is when a tenorman lifts his foot in the air. Great jazz is when he heaves a piercing note for 32 bars and collapses on his hands and knees.

"A pure genius of jazz is manifested when he and the rest of the orchestra run around the room while the rhythm section grimaces and dances around their instruments."

That's Charles Mingus's take on jazz - energy, improvisation and passion.

It's a long way from Grammy-winning Diana Krall's style.

The 43-year-old Canadian, who started playing piano at the age of four, is a controlled performer.

There's none of the raw soul-shredding of a Nina Simone or a Billie Holiday in her delivery, no playful, creative forays into the realms of scat singing.

Staying comfortably within range, Krall holds back, rather than emotes.

She plays with the words: subtle, gentle, sometimes ironic, sometimes yearning.

It's jazz that uses silences and sensitivity to create a mood, usually leaning towards a slow, even languid tempo.

It's easy-on-the-ear, if not exciting - and has won the singer/pianist plenty of fans. Krall has sat at the top of the jazz album chart for more than a decade now.

This Saturday she's at Kenwood, playing a selection of pieces from her latest album, The Very Best Of Diana Krall.

The night is one stop on a long world tour. Krall has already played Portugal, Spain and France.

After Hampstead, she's going to Oslo, and then she's off to Asia, playing venues from Indonesia to China.

To make things tougher, her husband Elvis Costello is also on tour - opening for The Police in the States. So Krall is alone on the road with the couple's 20-month old twins, Dexter Henry Lorcan and Frank Harlan James.

"My biggest challenge right now is being on a bus with two toddlers," Krall admits.

"I have to get them on overnight runs, figure out where the playground activities are for them in each new place, do my shows and be a full-time mum - all without Elvis.

"This is a completely new way of life. It's incredibly joyful and I feel like I have it all - but having it all is exhausting!"

There's no time off. When Krall does get a break from the tour, she's heading to the studio to record a new album and DVD.

She's working with Claus Ogermann, the arranger who worked with her on her 2001 album, The Look Of Love, and promises plenty of ballads and Brazil-inspired bossa nova rhythm.

"Ogermann brings a specific sound to the work he does," Krall says. "Intensely passionate and quite dark."

Krall doesn't say which songs she'll be adding to her repertoire but in the past she's thrown in some surprises alongside classics by the likes of Cole Porter and Irving Berlin.

Her forte, however, is in bringing her own sound to established favourites.

"One of my strengths is taking something apart and reinterpreting it - so the same lyric has a different message.

"I sing a song called But Not For Me, which was written by George Gershwin, and my band members were saying, "Man, I never knew that was such a sad song", because so many people sing it uptempo, as a joyful song.

"And I do I've Got You Under My Skin as a very slow bossa nova, where most people do it uptempo.

"I'm not saying there's a right way or a wrong way, just that there's a creative element."

That creativity rarely turns into Krall composing her own work.

But after her mother died of cancer in 2002, aged just 60, she says she found the songs she'd been working on too painful to sing. Instead, she started writing her own.

Her 2004 release, The Girl In The Other Room, featured several tracks she'd co-written with Costello and composed herself.

"The only thing I could do at that time was write my own music and I got deep into that.

"I got deep into Joni Mitchell - someone I'd always loved. But just because you love someone doesn't mean...just because you love Bach doesn't mean you're going to be Glenn Gould.

"Joni Mitchell - how can she write like that? That's why I don't want to write. How can she write like that?"

"I needed to do my own work and I'm glad I did it - but it's not something I'm putting all my energy into. I don't think I'm a very good composer."

What Krall does credit herself with is an emotional feel for the music she plays.

"My greatest strength as a musician is my natural feel. I have no technical ability whatsoever, minimal chops, but lots of heart and soul."

"To me, the root of jazz is all about the emotional, all about the feeling. As a jazz musician, you're trained your whole life to heighten your senses, so you can listen to five people all at once, and all improvise together.

"That has to come out in your personality. I'm over-sensitive to a fault. I'm a really intense person. I've just learned to deal with it."

Her outlets are skiing - which she does for three hours every day when she's at home in Vancouver - photography, the twins, and Costello.

"It's a very happy life at the moment," Krall says, as the interview ends. "It's an extraordinary life. I just want to enjoy every moment." She hesitates, and laughs. "Even if it does mean less sleep," she says.

Diana Krall is at Kenwood on Saturday. For tickets, call 0844 412 2706.