Girl allowed: Nicola Roberts on surviving teen stardom to become pop's next big thing

She was the 16-year-old who found fame on the original reality-TV talent show. And then came the hateful digs that would punctuate her career with Girls Aloud. Hugh Montgomery meets Nicola Roberts, the porcelain pop princess whose first solo album should finally silence the critics

Never let it be said that Nicola Roberts doesn't do smiles. Over the course of our time together she runs through a veritable repertoire of them. There's the demure simper with which she greets me in a London members' club. The excited grin when discussing "the music". The knowing half-smile that reproves a mischievous comment. The conspiratorial smirk after her PR comes over and hurries me to wrap things up. And then a beaming flash of the pearlies accessorising a firm(-ish) hug as I leave.

A famous person lifting the corners of their mouth in aid of good publicity? You might say this is not unprecedented. And yet charming, charismatic and forthright though she is, Roberts – one fifth of all-conquering girl group Girls Aloud – has a reputation to contend with. In 2002, when she, Nadine, Cheryl, Kimberley and Sarah won talent show Popstars: The Rivals and hit the tabloids running, she swiftly found herself dubbed the "moody one" of the band. Nine years on, and it's a label she's still tagged with, judging by my random sampling of some not especially pop-cultural- savvy friends. "I wasn't moody," she reflects now. "I was 17 years old and from a place which is very small and where people don't walk around smiling all day, they have problems... And I smile when something makes me smile. If I'm walking out of a club, and there are paparazzi there, what the fuck have I got to smile about?"

Now 25, Roberts seems poised to shatter some more preconceptions with her pretty darned fantastic solo album. For though she may come from a manufactured pop band, Cinderella's Eyes is anything but production line. The seeds of anticipation were sown with the lead-off single "Beat of My Drum". Neither overblown balladry (hurrah!) nor cod-raunchy R&B (double hurrah!), here was a spiky, savvy electro-pop anthem, complete with cheerleader-style chanting, that bore the influence of French house honchos Justice and art-pop-rapper MIA. It was also, for my mind, the song of the summer. "[There's a] sense of seaside-surreality, a 'British' pop sense that has been missing from the airwaves for far too long... a brilliant pop moment from an unlikely source," declared unlikely source NME. "Cheesy but super-cool" is the rather less guileful description we agree on, which I think just about nails it. Indeed, such cheesy super-coolness permeates Cinderella's Eyes, with sassy Girls Aloud-esque hooks sitting alongside rap segues and off-kilter electronics.

But even more than the music, it's the lyrics that mark Roberts out from the plasticky chart pack. Riven with anger and anxiety, they reflect a decade in the celebrity spotlight tainted by bad press and undue abuse. The result is self-revealing – but not, crucially, self-piteous. "Too young to buy my own bottle of vodka / So I begged the driver, 'Please I need another' / How funny that I was too young for so many things/ Yet you thought I'd cope with being told I'm ugly over and over", she spits in "Sticks and Stones", among other raw-to-the-bone observations. Best is "I", an opiated synth reverie which finds her cooing and wailing her way through a list of her hates and fears like the hybrid offspring of Kate Bush and Alison Goldfrapp. She's described it as "a funeral song": was her major record label bemused by such a deathly curio? "Yeah, at first, management were like, 'I don't get it.' But I was like, 'Well it's not your album,'" she recalls with knowing petulance.

Roberts is at pains to point out her creative independence. She tried working with a number of producers, she says, before hitting upon Parisian Dimitri Tikovoi – he understood "it was MY record... I have to own it", she notes, concurring that others might have patronised her for her girl-group roots. Other collaborators on the album include Mercury Prize nominees Metronomy and hipster-dance maestro Diplo. And one of her main inspirations for the album was hip-hop, because, "every lyric means something". Last summer, she was listening to a Radio 1 preview of Eminem's new album in a car when she started rapping some of the lyrics for "Stick and Stones" over the top. "The beat was so hard. It was like fuck you, fuck you!" she says, determinedly punching her fist into her hand. "So I went to Dimitri and said, 'I want the middle eight section to be like this.'"

Conversely, if the finished product brims with self-assurance, its genesis was altogether more timid. When she first started working on songs towards the end of 2009, she remained entirely secretive about it "because I didn't want the pressure of having to put a record out because I'd said I was making music". And even getting into the studio in the first place was a struggle of will. "We finished our tour at the end of June [2009], and then we said we were going to go on a break. I had the summer off, and then we did a gig with Coldplay in September, and then we finished that and it was like, 'Right, what do I do now?'" she sighs. "I couldn't see music in my future. Nobody had approached me with a deal [at that point] so it was like, 'Am I allowed to make [it]?' It made me really sad: how did I go from believing so much in what I could do to thinking music wasn't even an option for me?"

Roberts, after all, was nothing if not determined. As a little girl growing up on an estate in Runcorn, Cheshire, she would retreat to the garden to pen her own ditties. Aged 11, a Spice Girls performance in a holiday camp competition unleashed her inner pop princess, and a period of "auditioning for everything" followed. Indeed, her description of her burgeoning vocation is notable for its manically fairy-tale tenor. "I'd cry, I would be in bed and I'd be like, 'Please God, please God one day let me be a singer,' because I'd gone so far mentally with the dream that I had to become it, because it would have destroyed me if I hadn't. Every time I picked an eyelash, every time I had a birthday, every time I picked one of those plants in the garden which you blow, I'd make a wish. It was a constant want and then it just kind of spiralled."

And then her mum saw an advert on the telly for Popstars: The Rivals and the rest, as the girls might say, is a whole lotta history. Funny to think that, back in the early noughties, the TV talent show was a relatively innocent beast, free from today's freak showmanship and Cowellian sturm-und-drang. Roberts remembers her time on the show as a wholly happy experience. "At the first audition, we had to be seen by the producers, before the judges. There were 10 of us, and we had to stand up in front of each other and sing. I remember thinking, 'You're all shit,'" she says, widening her eyes, and, "'I think I can do this.'" Originally rejected before the finals stage, but thrown a lifeline when another contestant pulled out, she ended up coming second in the public vote for the band. And that despite the indifference of nominal manager/mentor Louis Walsh – the mention of whose name today provokes a delightfully insouciant scowl.

Walsh, however, proved to be the least of her concerns. At 16 years old, she was the youngest of the group, and a young 16 at that. On the one hand, she didn't know "how to use the washing machine or that you had to go the postbox to send post – I didn't know what post was!" On the other, she and her four comrades found themselves with more responsibility for their career than your average indie band after their relationship with Walsh distanced and they set about managing themselves. Rather than growing up fast, it was a matter of growing up fragmented. "I needed to go home for a sense of normality... so one day I'd be at the local chippy with my mates sitting in a Corsa waiting for the lads with a bottle of Lambrini, and then the next I'd be in our lawyer's office, signing and understanding contracts X, Y and Z because we didn't have management to explain them. I was two people the whole time, and I just couldn't deal with it."

Or make that three people, counting the Little Miss Miserable dreamt up by media and messageboarders alike. From day one, everything about Roberts was ripe for the picking at: her looks, her dress sense, her pale skin, her dress sense, and her misconstrued aloofness. And showbiz peers weighed in with their own uppercuts. Matt Willis, from skater-boy pop-rockers Busted, called her "a rude ginger bitch"; that venerable charmer Chris Moyles, a "sour-faced old cow". When I ask about the most hurtful comment ever directed her way, she declines to answer. "I can't bring myself to say because I get embarrassed by it. And I know that if I did, you'd feel uncomfortable."

If that's a deflection – "I'm a very comfortable chap," I protest – it's understandable: such was her embarrassment, she says, she suffered the taunts in silence rather than confide in family or bandmates. At the same time, her parents split up; "I felt I was on the brink a lot, like I had the whole world on my shoulders," she says. Was she depressed? "No. It wasn't like I couldn't leave the bloody house or anything," she says switching on the no-nonsense attitude. Having "said no to the shrink", to quote one of her lyrics, she eventually found solace in her own psychological acuity. "I got very deep as a person. I'm very good at reading people and I learnt to rationalise why they say or do [certain things]."

This dovetailed with a striking change in her appearance. A few years ago, she ditched the fake tan that's the sine qua non of the aspiring popstrel and embraced her paleness. Not only that, but she encouraged others to do the same by creating Dainty Doll, a successful specialist make-up range for porcelain skin tones. Her couture, meanwhile, has turned ever-more haute, just as she has become a regular front-row presence at fashion shows. These days, she can add the "stylish one" to her list of sobriquets, though she demurs at the term fashionista. "Oh, I don't get wrapped up in all that bollocks," she says, her Scouse accent noticeably deepening. "That whole judging from head to toe that goes on, not interested." Instead, as she sees it, "fashion can really give you an identity if you're looking for one and I think the more people that know that, the less identity crises we'll have in the world."

Indeed, appear to stray into "that whole judging" territory with Roberts at your peril. An offhand reference to her "skimpy" costume for the "Beat of My Drum" video is immediately rebuffed. "Is it skimpy?" "Well I'm not talking ridiculous..." "Knickers," she glares, a 25-year-old making this 28-year-old feel like a nascent Mary Whitehouse. "Do you know what? I'm young. I do not have any rules on clothes at all. It's about what I feel like on that day and" – her voice rises for the chorus – "if I wanna wear it, I'll wear it." Equally when I bring up her recent dental surgery – she had her teeth straightened and veneers fitted for the reported cost of £13,000 – it puts her on the defensive. "Surgery," she mutters disbelievingly. "It was a dental appointment." "I'm from a place where dentists get paid to rip kids' teeth out. NHS dentistry in the 1990s, my good God," she explains. "I always just wanted a nice smile, and I was conscious of it all time, and I'm happy. So I did, fuck it, everyone gets it done." Cue the next question.

It's certainly bizarre to think Roberts was ever portrayed as a wallflower: this is after all the girl who, in 2007, declared Gordon Brown "to be a little toad full of shite". Last February, she presented a BBC3 documentary, The Truth Behind Tanning, inspired by her own previous tanning obsession, in which she lobbied for a new law banning under-18s from sunbeds. It's since been passed, coming into effect into April. She is obviously made up by the result, though obviously unimpressed at the protractedness of the legislative process. "I don't understand how it takes so long to change a law when the whole nation wants it to be changed." And for the record, if she was too down on Gordon, she hardly seems more up on the new lot. "We're in so much of a mess, and I feel like if the government looked at things in black and white, rather than grey, things would happen quicker."

The irony is that Roberts herself seems anything but black and white: at once direct and guarded, vulnerable and indomitable, young for her years and old beyond them. These days, she's settled in the starry suburban enclave of Weybridge, Surrey, with her boyfriend of three years Charlie and pug dogs Ronnie and Reggie, but despite the accoutrements, she's not about to submit to the quiet life – familiar as she is with her local kebab shop. "I'm not ready to come out of being a girl. Between 16 and 23, I wasn't necessarily happy, so now I am, I want to kind of go back and do those years [again]."

When I ask if she ever imagines how her life would have panned out had she not earnt that last-minute reprieve in Popstars: the Rivals, the question sets her off immediately. "All the time. I will think about something constantly until I can rationalise it, but [in this case] I can't, no matter how many times I think, 'Why I am the person who got into the band? Why wasn't it the girl sitting next to me?' I'll never be able to figure that out, never be able to deal with it. It's a massive fucking thing: not many people grow up to be what they dreamt to be, but I did... Why did it happen to me? I don't understand it and I'll never be able to understand it and I don't like it." She makes living the dream sound about as much fun as waiting for Godot. But Roberts should be glad for the grey areas, I think: they are verily the making of a Technicolor pop star.

Nicola Roberts' single 'Lucky Day' is out today. The album 'Cinderella's Eyes' is out on 26 September