This weekend the Arcade Fire will play the Coachella festival in California, a two-day, 90-band blowout headlined by Coldplay and Nine Inch Nails. Three days later the band will kick off a three-week tour of Europe and the UK with a show in Manchester, but when they cross the Atlantic they’ll be leaving a member behind: 22-year-old Will Butler, who plays bass, keyboards, and percussion, is finishing his senior year at Northwestern. “There’s not a lot of rock stars that have to hurry back to class on Monday,” he says.

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Born in California and raised near Houston, Texas, Will and Win Butler have been playing to crowds since they were children. They often backed their mother, Liza, when she visited grade schools to demonstrate the harp. Liza’s parents–vocalist Luise King, who sang in a pop group called the King Sisters, and jazz guitarist Alvino Rey–hosted a family-oriented TV variety show on ABC between 1965 and ’69, and she and her siblings often appeared on it. “Grandpa used to describe it as the only show more white-bread than Lawrence Welk,” says Will.

Throughout these years, Will would come home from prep school and work on songs with Win during holiday breaks. “He’d be like, ‘Play this bass line’ or ‘I need someone to play piano.’ So we kept doing that,” Will says. “And it worked because we naturally shared tastes and a musical sensibility.”

That spring the band signed to Merge Records on the strength of an in-progress version of the album they’d mailed to the label. Even before Funeral came out, the Arcade Fire had stirred up a formidable word-of-mouth buzz with its uninhibited live shows. (The group’s wild man, Will uses everything within climbing range as a percussion instrument and likes to leap on his brother’s back midsong.) In September the disc was released and became an overnight sensation. For Will the highlight of the first few months was a concert at New York’s Irving Plaza in February, where David Byrne–who’d also been praising the band on his Web site–joined them onstage to sing Talking Heads’ “This Must Be the Place (Naive Melody).”