Several hours before he is scheduled to take the stage, Alex Turner, the guitarist and lead singer of the Arctic Monkeys, enters his dressing room and sits on an ice chest filled with water and energy drinks. It is not at all drafty inside, but Turner is wearing a jacket zipped to the neck and a blue knit cap. Like his three bandmates, Turner has bad skin, looks about fifteen -- he's actually twenty -- and still lives with his parents. These facts have not stopped the Arctic Monkeys from becoming a major sensation in their native Britain. When the band's first album, Whatever People Say I Am, That's What I'm Not, was released in the U.K. earlier this year, it sold more than 350,000 copies its first week, becoming the fastest-selling debut in British history. Rock icons from David Bowie and Mick Jagger to Oasis and the Strokes are all fans.

In the U.S., Whatever People Say debuted in the Top Forty after its February 21st release; the single "I Bet You Look Good on the Dancefloor" had already been in the iTunes Top Ten for a month. The band will launch a major U.S. club tour on March 13th in San Francisco -- all dates are already sold out.

The Monkeys themselves -- Turner; guitarist Jamie Cook, 20; bassist Andy Nicholson and drummer Matt Helders, both 19 -- seem to be wisely recoiling from the hype. They have declined offers to appear on the BBC's Top of the Pops and, pleading already scheduled tour dates, they skipped the Brit Awards, the U.K. equivalent of the Grammys. Tonight, playing a college campus in the sleepy English town of Norwich -- most famous export: mustard -- they are sandwiched in the second slot of a four-band bill, beneath the much-lesser-known indie band Maximo Park. Asked about the upcoming U.S. tour, Cook shrugs and says, "It's pretty hard to break America, innit?"

The band hails from Sheffield, an old steel town in northern England, best known, musically, for producing the unholy trinity of Pulp, Human League and Def Leppard. "We all sang 'Let's Get Rocked' every morning at school," Turner notes drily. The son of a secondary-school music teacher, Turner took piano lessons as a kid but hated theory and practice. ("My dad teaches me more stuff now," Turner says. "I'll be home, messing about with a song on the piano, and he'll say, 'What are you trying to do?'") The Monkeys formed in 2002; friends since high school, Turner and Cook had received guitars the prior Christmas and taught themselves a few chords. They began rehearsing every Tuesday evening. "Our early songs were bollocks," says Turner. "A lot of them had the word 'doobie' in them."

Because you smoked a lot of pot?

"No. Because it was a funny word for spliff."

In Norwich, the hangarlike, unadorned venue is packed with true believers when the Monkeys take the stage. The band's hook-filled songs are both taut and sprawling, often packing funky breaks, metallic crescendos and weird pop flourishes -- e.g., the falsetto backing vocals on "I Bet You Look Good on the Dancefloor" -- into a single song. Turner favors long, literary-sounding titles: "You Probably Couldn't See for the Lights but You Were Looking Straight at Me," "Perhaps Vampires Is a Bit Strong But . . ." He's most often compared with Mike Skinner, a.k.a. the Streets, and rightly so. Like Skinner, his lyrics deal with the pedestrian realities of ordinary dudes who hang out in bars and clubs, get hassled by doormen and have trouble making time with stuck-up chicks.

Before signing with Domino Records, the indie label that broke Franz Ferdinand, the Monkeys built up huge grass-roots buzz by passing out free CDs at shows to fans, some of whom began posting the songs online. When "Dancefloor" debuted at Number One last year, it blindsided many in the British music industry and wildly excited others looking for a way to use the Internet to save the record business. "It was completely accidental," Turner says. "We never posted any songs ourselves."

"We didn't do any promotion," adds Helders, who is wearing a bright-yellow T-shirt reading NO PROBLEM JAMAICA. "There were no posters around London. So newspapers and people like that thought, 'What the fuck is this? Must be the Internet!' Well, the song's pretty good, too."

Such rapid ascension has, naturally, come with its share of odd moments. "A tabloid found an ex-girlfriend of mine," says Helders. "That was kind of weird. I went out with her when I was twelve. Then Alex dated her when he was fourteen. She sold her story for, like, a grand."

"Last year at this time, we were driving around playing shows near Sheffield," says Turner, adding with considerable understatement, "now, it feels like we'll at least have a go at it."

Additional reporting by Brian Hiatt