Norah Jones. Dark ‘n’ moody singer of dark ‘n’ moody, jazz-ish songs. Before she was 26, had sold a bazillion copies - 30 million, to be precise - of her albums Come Away With Me and Feels Like Home, and won a mantelpiece-filling eight Grammys. Raised in Texas, the long-lost daughter of celebrated Indian musician and friend of The Beatles, Ravi Shankar - but she doesn’t like to talk about it. A planet-rattling music phenomenon disguised as a waif in a floaty dress who wouldn’t say boo to a goldfish. Or, as she puts it herself with a mocking, breathy whisper, the Norah Jones of public profile is “very romantic, very melancholic and very soft-spoken”.

But then there is the Norah Jones who is before me now, flopping about on a hotel sofa, merrily displaying sweat marks under her armpits. She is a small, cool, indie-looking girl, aged 28 now, with a big, throaty laugh and eyes you could drown in. This Norah loves Tenacious D, actor Jack Black’s spoof metal band, and is word-perfect on the lyrics to their elegant ditty F*** Her Gently; likes a few beers and a dance but is rubbish at the latter; and laid into George Bush on her third album, last year’s Not Too Late, notably in the song My Dear Country: “Nothing is as scary as election day/but the day after is darker who knows, maybe he’s not deranged.”

In the gloom of a London hotel suite, Jones sips at some mineral water and scrunches back her hair into a messy ponytail. She bites her nails and cracks her fingers. She wears cheapo (well, £45) silver ballet pumps, a nondescript pale blue cardigan, a burgundy Urban Outfitters camisole and Seven jeans. (”They’re seven years old,” she says proudly, “they’re the only ones that fit me.”) She looks like she has come to clean the room rather than live in it.

Norah Jones is punchier, edgier than we might have expected. And as we see in her debut film role, in Wong Kar Wai’s My Blueberry Nights, she is an accomplished actress too. Let’s call this version of the easy-listening superstar “NoJo” and ask her about snogging Jude Law.

“He is a wonderful, laid-back, normal person,” she says of her My Blueberry Nights co-star. “And there were paparazzi following him from the trailer to the set. And he really just tries to live his life as if it doesn’t exist. They didn’t care about me at all! But he’s a really good guy, considering the public life he’s had to endure. It’s unfortunate to have all the gossip columns have your picture in them.”

In the new film from the acclaimed Chinese auteur (Wong’s arthouse hits Happy Together, In The Mood For Love and 2046 all wowed the Cannes Film Festival), Jones plays New Yorker Elizabeth, who is reeling from a bad romantic split. She and a café owner (Law) bond over after-hours blueberry pie and smokes. In an attempt to sort out her emotions and her life, Elizabeth hits the road, waitressing her way across America.

In a Memphis bar, she encounters a separated couple, he alcoholic policeman Arnie (David Strathairn), she much-younger vamp Sue Lynne (Rachel Weisz) who turns heads wherever she goes. Travelling west towards Las Vegas, Elizabeth meets a young gambler (Natalie Portman) who is trying to score a fortune at a poker match and wrestling with a damaged relationship with her gambler dad.

Jones says she still doesn’t know why Wong Kar Wai asked her to be in My Blueberry Nights, not least because she had never acted before. “Hasn’t he seen me be awkward as a performer on stage?” she smiles. She remembers that he had been trying to meet her for some months. But at the time - early 2005 - she was in the midst of a world tour. Despite being a big movie fan, she had never seen any of his films so she watched In The Mood For Love. She loved it: “Wow, this guy is amazing - I’ll meet with him. Maybe he wants a song for a movie.”

But without auditioning her, Wong offered Jones the lead role in My Blueberry Nights - again, a response at odds with Jones’s image as a shy, retiring type who doesn’t seem overly comfortable in the spotlight.

“Yeah, which I agree with though!” she laughs. “I would be the last person I would choose to be in a movie! But there was something about him that I trusted, he saw something in me that he wanted. I don’t know what that was. Maybe it was an awkwardness or a shyness, a vulnerability. I have no idea but I do have a few years’ experience as a waitress. I can actually carry a tray of drinks, which was great - otherwise it would have been really hard.”

Wong insisted that the singer take no acting lessons. One explanation for his trust and enthusiasm is that the cult director is famously intense and experimental. “The way he makes movies is kinda like music. He rewrites the story to suit the mood that he feels from the actors, sometimes daily. Some stories changed very little from the first version I got, and some changed day to day. Jude said to me it was like a living story. And it’s true, it’s kinda cool like that - but I was terrified.”

At one point, Jones asked one of the producers - what if Wong’s gamble hadn’t worked and she was, in fact, a rubbish actress? The producer replied with a shrug that the director would “just fix it by taking away all my lines”.

She needn’t have worried: Jones is a soulful, quiet but powerful presence onscreen. My Blueberry Nights is a beautiful, meandering film, studded with exquisitely-shot scenes. Jones, according to co-star Weisz, coped admirably with Wong’s exacting methods. “Norah was brilliant,” Weisz tells me. “She’s a really natural actress. She’s very alive.”

Jones’s mother Sue raised her to be this way: real, but also laid-back. “My mom’s very grounding. She’s very nervous that I’ll change. To the point where sometimes she gets on to me for stuff I haven’t done yet. I’m like, Why are you being so mean!’ Because I don’t want you to be a diva!’ I was like, But I’m not being a diva yet!’” she cackles.

Jones, unsurprisingly, is no Britney-esque club-hopping casualty. She admits to a fondness for vodka martinis but has knocked her occasional cigarette habit on the head; a favourite indulgence is “eating my way across Europe” while on tour; the most outlandish rumour she’s heard about herself is that she and musician boyfriend Lee Alexander - a member of her band - were getting married. (”I don’t feel any rush. We already have a good commitment to each other.”) Nonetheless, is Mom worried that her only daughter will head down the road of vice and iniquity?

“Yes, I think probably from being around my dad for so many years. Not that my dad went down a road of bad vices, but just seeing the way people reacted to someone with fame and notoriety. I think observing that experience is what made her wary of the music business. She didn’t even want me to sign a record deal.”

Sue Jones was working for a concert promoter when she met Ravi Shankar on one of the Indian sitar maestro’s US tours. Norah was their sole child together. After their relationship ended, Shankar was largely absent from his daughter’s life; they were only reunited when Jones was 18.

“I’ve lived my whole life without having to be known as the daughter of somebody. And I didn’t want to start with music. Maybe I’m genetically more inclined to music but the music I make is so far removed from Indian classical music - I grew up in Texas! But I’m fine with talking about it now, because I feel like I don’t have anything to prove any more, although I still think I have a lot to prove to myself. But also people think of me separately from him now, and that’s great. I love my dad and we have a very good relationship now.”

She also inherited his musical skills, as Dave Grohl of Foo Fighters confirms - he invited Jones to play piano and sing on the band’s In Your Honour album. “She is positively the most talented musician I’ve ever been around in my life,” Grohl says. “And that’s including some heavies. She was unbelievable. We were absolutely stunned. She did two takes. And that was it. And she was sweet as sugar, man. Unassuming, modest, nice girl. A good hang!”

The Jones who was an 11-year-old Nirvana obsessive - “listening to Nevermind on my headphones in bed, air-drumming, going woah dude, this is awesome!’” - was equally thrilled. As she was when she performed with Keith Richards. She duetted with the Rolling Stones legend onstage at two Gram Parsons tribute shows, and has met him backstage at Stones gigs. She cringes whenever she sees the DVD of the Parsons shows - sharing a mic, she looks like a little girl who’s about to kiss Keef. What does he smell like?

“He smells soooo goood,” she says lasciviously, almost smacking her lips.

So he doesn’t reek of greasy hair, fags and wrinkly old leather?

“No. His manager told me it’s amber that he wears. I dunno if it’s an oil or something. You’d think he’d smell like patchouli And he’s a wonderful guy. He’s been so nice to me. His hands look like a tree, a knotty, knobby tree. He’s a character,” she beams. And just for a moment, Norah Jones looks like what she is: an unassuming 20-something kid who can’t believe she gets to meet her heroes - and who doesn’t understand that some of them are just as psyched to meet her.

Jones stretches out on the sofa and waggles her toes. She says she loves her spangly shoes, “because I can wear them to dinner and feel like I’m dressed up even when I’m not”. Which is handy because tonight Jones is dining at Soho House with Natalie Portman - the two have become firm friends after making My Blueberry Nights.

“I love Norah, she is a sweetheart,” Portman told me earlier, with gushing - but sincere - enthusiasm. “She knows what she’s doing.”

Two months later, I meet Jones again, this time in the New York offices of her label, Blue Note, a short walk from the apartment she shares with Alexander in midtown Manhattan. Her look today is student chic: a cap like Fidel Castro’s, the same jeans, a tiny nose stud, and a sleeveless green and brown top that reveals the birth mark she mostly keeps hidden: a scar-like discolouration running from her left hand up her arm and down her back. “It’s, like, totally gnarly,” she hoots, ramping up the Valley Girl-speak that she’s belatedly realised, with some mortification, that she tends to lapse into in conversation.

She loves the New York music scene, on which she is something of a fixture, pursuing a variety of extra-curricular musical activities. But she likes to keep them quiet, lest the fame of “Norah Jones” - the one who, last year, with Not Too Late, topped the album charts in five continents - gets in the way of her having a boozy, muso time in a late-night bar.

After some prodding she reveals the name of the other bands she plays with in New York bars: El Madmo, a pop/rock outfit for which Jones and pals don wigs and silly costumes and who have made an as-yet-unreleased album; and The Sloppy Joannes, who do Hank Williams and Kris Kristofferson covers. Given her love of rock and a boozy boogie, might some of her side-bands’ hair-down raucousness make it onto the fourth Norah Jones album?

“I don’t know if I’m gonna keep those things separate. I think if I didn’t have those bands I’d probably be more likely to bring that musical stuff in. Maybe I’ll never put out another Norah Jones album and I’ll only be in other bands.”

We walk the rush-hour streets of Manhattan together, heading for a little festive market in Union Square, she wrapped up in an ankle length overcoat. No-one usually recognises her, she says, although her dark looks mean she is often asked for directions in Spanish. At the market, Jones toys with a pointy woollen hat and coos over some craft stuff made out of felt, but ends up buying nothing.

“I’m pretty thrifty,” she says. Of the untold millions of dollars she has earned since bursting onto the international music scene in 2002, her main extravagance has been to fit a studio into her apartment - she and Alexander recorded Not Too Late there - and to buy a place in upstate New York, in the Catskill Mountains. “Lee’s into cars,” she smiles affectionately, but her other hobbies run to reading, painting (”kinda bold colours, kinda modern art - I’m not very good”) and eating.

“Food is probably one of my biggest vices - I love to buy dinner for my friends. I’m learning to enjoy myself. Even then, I’m not that extravagant. I might order a nice bottle of wine. But not like my manager or certain people at the label, who take you out and spend ridiculous amounts. You can go for a really nice dinner and not spend thousands of dollars.”

This is Norah Jones, a sublimely talented multimillionairess you might mistake for a pub-loving, chilled-out student. No wonder she’s so natural on the big screen. Wong Kar Wai knew what he was on about, and Ma Jones would be proud.

My Blueberry Nights is showing as part of the Glasgow Film Festival: Cineworld Renfrew Street, 8.45pm, February 17 and the Grosvenor, 6.30pm, February 18. It is released nationwide on
February 22.

The Sunday Herald is media partner of the
Glasgow Film Festival.

www.glasgowfilmfestival.org.uk