The Britpack - Our new generation of movie stars takes Tinseltown

In a fortnight's time, 10,000 people will file into London's O2 arena for the UK premiere of Prince Caspian. It will be, the producers trumpet, the "biggest single-screen, shared audience experience ever". But then, as the second instalment in Disney's Chronicles of Narnia series, it's a pretty big film. The first, The Lion, the Witch and the Wardrobe, grossed $745m worldwide. Hopes are high for Prince Caspian, which has already taken $167m at the box office, hitting the No 1 spot in America and 12 other countries.

And on whose rather slight shoulders does responsibility for the success of this multi-million dollar franchise currently rest? Those of an unassuming and, until now, unknown 26-year-old from Wimbledon, south-west London, called Ben Barnes.

The casting of Barnes – whose only previous film experience was a blink-and-you'll-miss it role in Stardust – as the eponymous hero might be seen as an uncharacteristic piece of risk-taking for the typically cautious, bucks-orientated Hollywood studio. In fact, it's a reflection of the latest trend in a town that is constantly on the look-out for the next big thing. And at the moment, the next big thing is young, little-known British actors.

Barnes is just one of a pack of fresh faces to take Los Angeles by storm and swipe leading roles from under the noses of their American counterparts. Andrew Garfield was cast by Robert Redford to play an overprivileged, undermotivated Californian frat boy opposite his own idealistic college professor in Lions for Lambs, while Boy A, a Channel 4 film for which Garfield won the best actor Bafta, has been picked up by the Weinstein Company for cinema distribution in America and Europe.

At the tender age of 26, Jim Sturgess already has two Hollywood leads in the bag – as Jude in Julie Taymor's Beatles-inspired musical Across the Universe, and as the geeky MIT student-turned-card shark in 21 – as well as a supporting role playing the brother of Natalie Portman and Scarlett Johansson in The Other Boleyn Girl; he will next be seen in Crossing Over, an ensemble film about immigration, with Harrison Ford and Sean Penn, that is being touted as the next Crash. And then there's erstwhile History Boy Dominic Cooper's upcoming turn as the romantic lead, Sky, in the big-budget film version of Mamma Mia!, and Ed Westwick, a 20-year-old from Stevenage who's gained legions of fans for his role as the Upper East Side trustafarian Chuck Bass in Gossip Girl and has won a leading role in S Darko, the follow-up to Donnie Darko.

"They have the acting chops – that's the No 1 thing – and then they have physical appeal. Handsome young men who can act? Wow, what a concept!" says Steven Gaydos, executive editor of Variety, who picked Garfield as one of the magazine's Ten Actors to Watch at the Hollywood Film Festival last autumn. "Tom Cruise has had an incredible run of almost 25 years at the top, but he's in his forties now and the younger audience may want the Tom Cruise who is 27. Who is that?

"Maybe it's Jim Sturgess, maybe it's Ben Barnes, maybe it's Andrew Garfield. Hollywood wouldn't exist without the continual renewal of acting talent from the UK. In the past, an actor probably established themselves a bit more in the UK and then transitioned over here. These actors are so young and their breakthroughs are in movies where they're not even playing English people – that's an interesting phenomenon. But Hollywood has been in love with British acting talent since the very beginning."

It's true that they are not the first British actors to make it big on the other side of the Atlantic. Directors and producers have long plundered our home-grown character actors to provide baddies, eccentrics and, in the case of Hugh Grant and Colin Firth, charmingly reserved romantic heroes. But there's something different about this new wave who, with their flawless accents and perhaps the odd spritz of fake tan, are eschewing typically British roles in favour of the meaty leads.

It's been happening in American television studios for some time now. Hugh Laurie has won Golden Globes for his role in House, Dominic West fronted five series of The Wire, and the former soap actresses Anna Friel and Michelle Ryan seized the leads in Pushing Daisies and Bionic Woman respectively. There have been leading roles for Brits in everything from Ugly Betty and Nip/Tuck to CSI and Boston Legal. As Sophia Myles, star of the CBS vampire drama Moonlight, said recently: "Play a British accent and you are the butler or the baddie. Do American and you can take the world."

If you're looking for signs that the new Brit pack has arrived in Hollywood, a 10-storey billboard of Barnes on Sunset Boulevard is persuasive proof. "I had to pull over and buy a disposable camera and take stupid pictures of myself in front of it," Barnes says. "Initially it's surreal, then you feel a bit embarrassed, then you smile to yourself and feel flattered and a little bit awkward – it's everything you'd expect, really."

Prince Caspian is his first leading film role and he had to complete a rigorous "Narnia boot camp" training of sword-fighting, accent-coaching and horse-riding before the seven-month shoot. "I rang my mum and said, 'Have I been on a horse?' She dug out a photo of me on a Shetland pony, aged six. I knew I'd been on a horse at some point and figured, 'How hard can it be?' Then I got there and found out." He continues: "The scale of it can be very intimidating. But the character is supposed to be anxious for most of the movie, so I think that helped."

He had reason to feel anxious. His only previous experience on set was a couple of days filming Stardust, in which he played the younger version of the hero's father in a flashback. "Everyone asks me how it was to work with Robert De Niro and Michelle Pfeiffer, but I never met them," he says. "Still, it stood me in good stead. It's amazing what a little scene can do if people see it and respond to it."

Before that, Barnes had been progressing steadily with a respectable, if accelerated, career as a jobbing actor. "I hit every rung of the ladder once," he says. He read English literature and drama at Kingston University where he briefly joined the cheesy boy-band Hyrise, who were longlisted as the UK's V C Eurovision entry in 2004 ("I dread people bringing it up. We had one song and we sang it once, it's not interesting") and spent a couple of years in theatre and daytime TV before he made the bold decision to go to the States to seek his fortune.

The first role his agent put him up for was a lifeguard who's eaten by a shark. "I came off the plane, pasty, skinny and wearing a black shirt. I went to the audition and there were 20 guys there in vests and shorts with tans and muscles. Honest to God, they were comparing calf muscles in the waiting room. I went outside and rang my agent and said, 'This is ridiculous, I'm never going to get this.' He said, 'Just think of it as a challenge.' I was so furious by the time I got in, I got a little bit over-emotional and they offered me the part. They never made the film, of course – it was a rubbish script."

Garfield's story of his first Hollywood audition, for Lions for Lambs, has a similar ring. "I thought never in a million years would I get it, so I wasn't actually that panicky," he says. "I just enjoyed the idea of auditioning for Robert Redford. When he brought me back in for a screen-test, that's when it really got scary. I didn't see the character like me, I saw him with a more streamlined nose, much bigger pectoral muscles and biceps. Physically I didn't feel right. I was trying my hardest to convince him that I could get there. And it seemed to work, funnily enough."

So what is it about these – in their own words – pasty-faced, skinny British boys that so appeals to the casting directors? "British actors come at acting from a slightly different angle," Sturgess says. "Because a lot of the films are cast out there, they are so used to the angle from which the Americans, and certainly the young guys from LA, are coming at it, that I think it's interesting for them to find these English actors who maybe approach acting from a different place."

In Sturgess's case, this different place was a distinct lack of interest in acting and a passion for music, in the guise of his band Dilated Spies. "With Across the Universe, they were looking for someone who was an actor who could sing or a singer who could act," Sturgess says. "I guess I fitted the bill." His work on the film has led to him being touted as the superhero lead in Taymor's next Broadway venture, Spider-Man: The Musical, with music by Bono and The Edge. That, in turn, led Entertainment Weekly to throw his name into the ring as a possible youthful Superman in the new Justice League movie. As Hollywood buzz goes, it doesn't get much louder than that.

"It feels like there's a real excitement about British actors," Garfield says. "I can't really figure it out. I get surprised every time someone thinks I'm good. But maybe it's the training we go through that our generation of American actors don't seem to be in touch with. The majority of young people just want to be stars and don't really care how they get there. I think of it this way: English actors go to drama school, or they try to, and American actors go to the gym."

It's true that these actors have spent a considerable part of their young lives honing the craft. Garfield attended the Central School of Speech and Drama and spent three years doing theatre in Manchester and London; Cooper graduated from Lamda and went straight to work with Nicholas Hytner at the National on His Dark Materials and The History Boys; Westwick's first role – in Anthony Minghella's Breaking and Entering – arose from a summer school at the National Youth Theatre; and both Sturgess and Barnes spent their teenage years performing with the National Youth Music Theatre before studying drama at university.

But there's also a fairy-tale, star-is-born element to their stories. Garfield was in the National Theatre's trilogy about teenage life, Burn/Chatroom/Citizenship, when he was spotted from the stalls by Stephen Daldry, who immediately called him in for a screen-test. That particular project never came to fruition, but Daldry's casting director picked up Garfield's tape and called him in for Lions for Lambs.

Sturgess's career took off after an actor who saw him doing his one-man student show in Manchester went back to London and recommended him to his agent. And

Prince Caspian's casting director Gail Stevens contacted Barnes after seeing him play "strutting peacock" Dakin in The History Boys in the West End (a role originally played by fellow Brit pack actor Cooper).

But Barnes's big break was marred by a row with the National Theatre about having to leave the production six weeks early. "I don't really like thinking about it," Barnes says. "It was always my dream to work at the National Theatre. I'd been going there since I was 10 with my dad. I taped one scene [for Caspian] and thought nothing of it. Then I did a screen-test and got offered the part a week later. It was in the middle of the night and I was running around the house screaming, completely overexcited. And then after about five seconds I was thinking about the play and feeling awful. I felt sick for three weeks. But I thought it was the kind of thing where you'd always wonder, 'What if?' for the rest of your life."

Garfield says: "Obviously there's something very seductive about movies, which can be attractive in a bad way if you're doing them for the wrong reasons – for money, or for fame. I hope I won't ever do that. I don't feel at home in LA, I feel like I'm on holiday. It's nice to dip your feet in occasionally, but I think it's probably quite unhealthy to spend too much time there at once.

"When I was there for Lions for Lambs, before I met my girlfriend out there, I was on my own. It was very difficult. I felt I had to hang out with my agents and managers all the time. Whom I love, but it was all parties and places you go to to be seen. It's pure vanity and it's kind of laughable."

Barnes says: "I like LA for a couple of weeks at a time. I like the sunshine and I like the fact that when I'm there, exciting things can happen. But then I want to go home. I'm not saying that I wouldn't go out there for a year or so if I thought it was going to help, but I couldn't settle out there." This week, he attended his first major red-carpet event, the MTV Movie Awards. "It was all right. Coldplay were brilliant," he says. "When Johnny Depp came on the stage, even though he was mumbling his way through his acceptance speech, everyone's jaws just dropped. I was looking around thinking, 'But he's not saying anything.' Everyone's faces were a treat, including mine."

So is Barnes getting mobbed in the street yet? "A little bit. I haven't been to Tesco since the film came out, and it hasn't even come out in England yet. We'll have to see."

'The Chronicles of Narnia: Prince Caspian' is out on 26 June

Ben Barnes

Barnes, 26, made his professional debut at the age of 16 in a National Youth Music Theatre production of Bugsy Malone. He went on to study English literature and drama at Kingston University. His first movie role was a bit part in last year's Stardust. He was playing Dakin in The History Boys in the West End when he was spotted and cast as the hero of Prince Caspian (opposite page). This month, he will appear in the low-budget British film Bigga Than Ben at the Edinburgh Film Festival. Next up are Easy Virtue, an adaptation of a Noël Coward play, with Colin Firth and Kristin Scott Thomas; the lead in Dorian Gray, directed by Oliver Parker; and the third Narnia film, The Voyage of the Dawn Treader.

Dominic Cooper

Cooper, 30, left Lamda and worked for several years with Nicholas Hytner at the National Theatre, eventually landing the plum role of Dakin in The History Boys. He has played similarly caddish roles in the British film Starter for Ten and in Andrew Davies's Sense and Sensibility. His next major role is Sky in Mamma Mia!, with Meryl Streep, to be followed by The Escapist with Joseph Fiennes and The Duchess with Ralph Fiennes and Keira Knightley.

Ed Westwick

Westwick, 20, is the toast of New York for his role as Chuck Bass, the Upper East Side cad, in Gossip Girl. A National Youth Theatre summer course led to minor roles in Breaking and Entering, Children of Men and Son of Rambow. He's won the male lead in S Darko, sequel to Donnie Darko.

Jim Sturgess

Like Barnes, Sturgess came to acting through the National Youth Music Theatre. He studied performance at the University of Salford and was picked up by an agent on the strength of a one-man show he put on in Manchester as a student. After being cast as the romantic lead in the Beatles musical Across the Universe, he gained a supporting role as George Boleyn in The Other Boleyn Girl, and the lead in 21. His upcoming films include Crossing Over, with Harrison Ford and Sean Penn; Fifty Dead Men Walking, set in 1980s Belfast; and Philip Ridley's Heartless. He's workshopped the lead role in Spider-Man: The Musical on Broadway and has been slated to play Superman in Justice League. ]

Andrew Garfield

Garfield was born in Los Angeles in 1983, but moved to Surrey at the age of three. By the time he left Central he had two major theatre roles under his belt, in Mercy at the Soho Theatre and the lead in Kes at Manchester Royal Exchange.

In 2006, he was anointed Outstanding Newcomer at the Evening Standard theatre awards for Burn/Chatroom/Citizenship at the National Theatre. He then won the role of Todd in Robert Redford's Lions for Lambs. In April, he was awarded the best actor Bafta for Boy A, in which he played a young man who committed a brutal murder as a child. The film has now been picked up by the Weinstein Company.

Garfield has just finished a starry reading of Eugene O'Neill's Mourning Becomes Electra, with Jennifer Jason Leigh and Maggie Gyllenhaal, at the Roundabout Theatre Company in New York. He will next appear in Terry Gilliam's The Imaginarium of Doctor Parnassus, alongside the late Heath Ledger and Johnny Depp.