From a bleak north London council estate to a sun-filled LA record label office, N-Dubz have had quite a journey. In just three years the cutting-edge, urban vocal trio have had an unprecedented impact on modern youth culture, introducing a nation to catchphrases like “Na-Na-Naiiii” and re-establishing the wearing of floppy hi-top hats.

They’ve split both critics and music fans, but Tula “Tulisa” Contostavlos, the only female member and self-declared mother-hen of the threesome, lets the figures do the talking.

“No other urban act has sold that many albums consistently. Three albums in a row went platinum and no other act has done that,” she says. “If anyone tries to put us down, I just say ‘album sales’!” With four MOBO awards, a Brit nomination, a Sunday Times bestselling book, a popular reality TV show and a recent signing to US record label giant Def Jam to their name, it looks like the band are set on nothing but global domination.

The daughter of Mungo Jerry star Steve Contostavlos (“When I was young I used to go to the studio, get on the microphone and try and record my own remix of Disney’s The Little Mermaid,” she laughs), Tulisa’s tough upbringing has been well documented – it was from these dark days that the band sprung forth.

“I just thought ‘Where’s my life going?’ I don’t want to spend the rest of my life in a one-bedroom council flat with my mum. Music was my way out. I had to make it. I didn’t have any other choice,” she says.

Inspired by the music of Michael Jackson, the band (comprising Tulisa, cousin Dino “Dappy” Contostavlos and school chum Richard “Fazer” Rawson) have been around since 2000, performing under the monikers Lickle Rinsers Crew and NW1. Pushing their music on the underground scene, the band’s material started airing on urban/hip hop TV outlet Channel U before major record labels came knocking. Selling more than a million copies, their debut album 2008’s Uncle B launched the trio into the media spotlight – a spotlight that soon focused on their personal lives as much as the music, with Dappy’s offstage antics regularly making the headlines.

“At the beginning we didn’t really know what we were getting into. I just wanted to be a musician and have everything that came with it. As I got older, I became my own person and realised I didn’t like the attention,” says Tulisa.

“I don’t like the press building up people because of what they do for a living. We should be building up young people who have done something inspiring in their lives. I get that what I do can be inspiring but I’m not a celebrity. I’m not anyone special – I just got lucky.”

Sights are now firmly set on cracking the US market. Recent album Love. Live. Life. is the bands first release on influential American label Def Jam and a slew of producers – from fellow Brit Mr Hudson to Blink 182’s Mark Hoppus – have helped create a polished, musically diverse album that takes in everything from free- flowing rap to squealing guitar riffs.

Tulisa is characteristically down-to-earth about their American onslaught. “Every challenge we’ve faced in the UK we’ve got to face again – I’m not nervous as we’ve got nothing to lose,” she says. “If it fails, at least we tried.”

Support from Professor Green, Starboy Nathan and Ny.