Apr 23, 2009, 9:10 GMT
Green Day were nearly "killed" by the making their new album.
The band's frontman Billie Joe Armstrong worked so hard on the band's LP '21st Century Breakdown' he was nearly hospitalised.
Describing how determined he was to better the band's last record, Billie Joe told Britain's The Sun newspaper: "This is the album that could have killed us. We had set the bar so high with 'American Idiot'.
"We all became sick as dogs. I was close to being hospitalised but they caught me in time. I had the boogie woogie flu!"
Billie Joe also revealed he his latest weapon in his songwriting arsenal is a BlackBerry mobile smartphone.
He added: "I got a BlackBerry and started to write down every idea for a lyric on it.
"I had many a sleepless night where I'd get something and have to get up and tap it into my BlackBerry."
He also thinks the band were encouraged to experiment on the new album - released on May 15 and billed as a "punk opera" - because of the support they received for 2004's universally acclaimed 'American Idiot'.
He added: "We had the opportunity to be more creative than ever before because we have a lot more listeners out there."
The band has also announced they will tour across North America in July and August.
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