One Direction: the fab five take America

'My bum's ready!" says Harry Styles, one fifth of One Direction, face down on the floor of the band's dressing room. He has yanked his Calvin Kleins down just a touch to reveal the top of his bottom, waiting for a doctor to arrive to administer a V12 vitamin shot. It's a sight that several million teenage girls around the world would die for; several hundred are right this minute camped outside every entrance to Radio City Music Hall in New York City, sending themselves into paroxysms at the thought of the merest glimpse of these boys. So no matter that to an observer more than twice the age of dreamboat Harry, he has the mien of a normal 18-year-old, goofing and lolling about, albeit one with recourse to expert medical assistance to boost his flagging energy levels.

If One Direction were all shattered, it would be forgivable.

Assembled during the seventh series of The X Factor in late 2010, the band flopped to third in the competition, but since then have signed a £2m deal with Simon Cowell's label, Syco, scored the fastest-selling debut album in the UK last year, won a Brit award for best single (as voted for listeners to Capital FM – not Radio 1, as they misspoke at the ceremony) and have announced a whopping 40 arena tour dates for next spring; and as the country's hottest boyband, they're inevitably enormous in territories such as Sweden and Australia. But the real news is this: next week, their debut album, Up All Night, has a fighting chance of hitting No 1 in America in its first week of release.

It has been a long time since a British band in this mould enjoyed any kind of success in the United States: it didn't happen for Westlife, or Take That. In fact, the name that trips off the tongue for most US observers is of a very different vintage, and more distinguished pedigree. "Now at 8.39am, with the group that some people are saying are inspiring the next case of Beatlemania …" says the presenter on Today, the biggest breakfast show on US TV. "Odds are if you do have a teenager in your house, a pre-teen girl, she's already obsessed with One Direction."

The report that follows charts the band's progress around north America on their current promo tour: in Boston, there is hysteria at a mobbed mall; in Toronto, the police are called to clear the street when fans surround the band's hotel. Bill Werde, a representative from Billboard magazine, says: "There's a lot of possibility here, there's a lot of upside ... that level of talent with those kinds of looks ... it's really a perfect storm for a massive, massive successful phenomenon."

Pace their album title, the boys, too, have been up all morning – starting at 8.50am, when Niall (Horan, the Irish, blond one) is the first to go into grooming at their midtown hotel. Then the five of them are smuggled into a black SUV to head to the studios of KTU 103.5 FM to record an interview that is subsequently syndicated to 31 US cities and to perform and take part in a live chat with fans. Forty-odd will be in the audience; at least half-an-hour before they arrive, at least 100 more are camped outside, hoping for that vision of the beautifully coiffed Harry or Niall, Zayn (Malik), Louis (Tomlinson) or Liam (Payne).

In the end, the vehicle takes the back entrance, but the girls – in constant communication through their cellphones – are wise to the move, and rush round, only to be forced back by security guards. A metal grille descends, and the boys are bundled out and into a service lift.

"So, first of all," says one flunkie among the dozen-odd surrounding them, "it's an interview with a DJ ... he's called Jagger."

"Mick Jagger," says one of One Direction, who might be Harry. "Yes, but don't expect any … moves like Jagger!" comes the rather flat retort.

Bustled through the building, the band only stop to gaze at photos of past visitors – the likes of Justin Bieber and the Jonas Brothers – and when I speak to Jagger ("No, that's just it – that's my name"), he attributes some of One Direction's success to a similarly shaped gap in the American market. "Since Backstreet Boys and 'N Sync, and the odd group like 98 Degrees, we've not really had a boy band in the US, so this is really refreshing," he says. He even mentions the idea of a new British invasion, citing the US success of Jessie J and that of another band, the Wanted, whose Glad You Came recently peaked at No 4 on the Billboard Hot 100. "It's definitely a plus for us that One Direction are from the UK," he says. "This is very exciting for us right now."

The interview with the audience that follows is familiar to any student of pop history in all but the detail – with one key exception. The audience is drawn from New York and its surrounds – as well as "Hogwarts!", as one girl chirrups. "Do you see yourselves making America your second home?" asks the host. "You can come and stay at my place any time!" interrupts another. The boys' answers are anodyne and noncommittal. Auditioning for X Factor was "absolutely terrifying"; the funniest thing they have been hit with on stage was a carrot; they all like Bruno Mars, except Harry, who prefers Coldplay's Chris Martin; their album has "faster songs, slower songs ... some mid-tempo songs"; success in America "just hasn't sunk in yet"; Niall – or is it Louis? – does the smelliest farts.

The difference is this: the host is taking questions from the audience, but the band are also peering at a couple of laptops perched in front of them. On screen, they're bombarded with a further set of questions posed by 23,000 fans, who have joined in for a webchat. That smashes the figure of 7,000 who signed up for the same chance to talk to Bieber. And this is where further explanation for One Direction's dizzying US rise can be found.

Traditionally, the business of breaking America took months of arduous slog, visiting endless radio stations across the country known only by confusing acronyms. But What Makes You Beautiful has only been at radio for these two weeks of the band's US jaunt; it charted at No 28, which may not sound impressive, but that was still the highest Billboard Hot 100 debut for a UK act for 14 years.

Sonny Takhar, the MD of Syco, attributes the speed at which everything is happening to the power of social media. "Sometimes you feel the song's the star, but it's not like that here - it's the act," he says. "It's a real moment. Social media has become the new radio, it's never broken an act globally like this before."

At Radio City Music Hall – aka "the Showplace of the Nation" – a straw poll of about 50 fans tells the same story: almost without exception, the girls discovered the band through Twitter and YouTube and (especially) through Tumblr, an application that works so well as a digital scrapbook: just perfect for teen pin-ups. Why make do with one Bieber when you can have five? And while management employs a social media team, the boys all tweet themselves, which helps create the illusion that they couldn't be any closer to their fans.

(The ghost at this feast is Takhar's boss, Simon Cowell. Before meeting One Direction, I had assumed that, as the star of American Idol and creator and star of The X Factor USA, he would used his muscle in the US to put One Direction in the spotlight, but there's no sign of him in New York, and the boys and their camp insist that he's played next to no role in what has happened so far.)

Tonight, the group are actually second on the bill to Big Time Rush, a boy band created by US TV station Nickelodeon, but by far the greater number of fans in the 6,000-strong crowd are wearing One Direction T-shirts. Many of these are lovingly homemade, such as the one sported by Morgan, who is 16 today and has travelled from Philadelphia; hers says, in a multicoloured lettering, "Soon to be Mrs Horan", a reference to Niall.

There's little in the way of a stage show – just a One Direction banner at the back of the stage and a scene-setting video that shows the boys larking about in a camper van, introducing each (and their likes and dislikes) in turn. Nor do the five attempt much in the way of choreography when they do take the stage. But they can sing, and the material – the slow songs, the fast songs, the mid-tempo songs, the product of 22 credited songwriters excluding the boys themselves, who get co-credits on three numbers on the album – is targeted at its market with precision accuracy: "what makes you beautiful" is – of course – that you don't realise that you are ... And the response? The response is extraordinary: one of One Direction's two managers claims he has seen a reading that shows the screaming reached 104 decibels – a figure comfortably beyond that at which sustained exposure can result in hearing loss. And having been surrounded by the hysteria, when an old adage about there not being a dry seat left in the house also came to find, it was easy to believe him.

Afterwards I speak to Meaghan, 17, from Long Island, and her 16-year old friend Carli, from New Jersey, although they're finding it hard to get their words out. Does it matter that they're British, I ask? "That just makes them cuter!"

And what else do you like about them? "EVERYTHING!"

The following afternoon, I see the boys in their hotel, the entrance to which is surrounded by girls. Up on the 12th floor, Paul, the tour manager-cum-"glorified babysitter" (as they describe him) is sitting on the floor, nursing a hamburger, warding off fans who make it this far. It's a scene uncannily reminiscent from a present that I've brought with me: a DVD of the Maysles brothers' seminal film of the Beatles first visit to America in the spring of 1964. It could easily have been the grandmothers of the girls sneaking around the hotel now who were there to mob the Moptops.

Dressed down and in close-up, these five boys couldn't be more perky or sweet, even if they have been media-trained to within an inch of their lives (expertly fending off a question about how humiliating it must have been for Big Time Rush the previous night, for instance). I ask about the toll the relentless pace is taking on them and Liam (it was definitely Liam) says, "Part of me just wants to go back to Wolverhampton and play in a field," but he didn't really mean it.

We don't have much else to say to each other (I blanche at asking Harry about his recently ended romance with a TV presenter, Caroline Flack, 32, the only bit of sort-of scandal to touch them thus far), but they do seem thrilled with my present, while all along I'd thought they might not even know who the Beatles were or are. They promise to watch it when there's time, but time is what they don't have now: after our 20 minutes are up they have to leave for rehearsals: tomorrow they make their national TV debut in the US for the same Today TV show at Rockefeller Plaza, in front several thousand hysterical girls; the album comes out the following day, and next week they'll know if they are No 1.

Two days later I receive an email: Thanks so much for the DVD – incredibly thoughtful of you. We all watched it last night and it was really interesting. We didn't realise quite how cheeky they were so I think we will definitely be borrowing some of their lines!

We can really relate to how they must have been feeling coming over here and much like us, having your band mates around keeps us all grounded and makes the madness a little easier to deal with. That said, it's a very surreal time (amazing but surreal!) for us and for anyone to even suggest a comparison between us and the Beatles is extraordinarily humbling and we're so grateful to be here and have this opportunity. Thanks again for the dvd and coming out to see us. 1D x