New U2 album Songs of Innocence offered for free on iTunes at Apple's iPhone 6 launch

Songs of Innocence is the largest album release of all time

Bono and Apple CEO Tim Cook announce U2's surprise new album at the iPhone 6 launch (Getty Images)

U2 have given away their first album in five years for free to 500 million iTunes customers.

The Irish rock band performed live at Apple’s iPhone 6 launch in California, where the surprise news about their record was announced.

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Frontman Bono described the release of the 11-track Songs of Innocence as “mindblowing”. It will be available in 119 countries worldwide – the largest album release of all time, according to Rolling Stone.

“The most personal album we’ve written could be shared with half a billion people – by hitting send,” he said. “If only songwriting was that easy.”

The album is described on iTunes as “rooted in the band’s early and lifelong influences including The Ramones, Bob Dylan and The Clash”. One song, “Iris (Hold Me Close)” is a “beautiful homage to Bono’s mother”, with other tracks including “Raised by Wolves” and “Volcano”.

Rumours of a new U2 album had been circulating recently, but a free, surprise release was unexpected. Details of the group’s deal with iTunes remain unknown, although they have partnered with Apple before. In 2004, a special edition iPod was released, etched with the four U2 members’ signatures.

U2’s No Line on the Horizon reached number one in the UK in 2009 and eventually hit the five million sales around the globe, but Bono was reportedly disappointed with its reception.

Several major artists have released surprise albums of late, most notably Beyoncé.

Radiohead released In Rainbows in 2007 and initially allowed listeners to pay what they thought the album was worth.

Prince’s Planet Earth was given away for free to Mail on Sunday readers, also in 2007, before 20Ten came with copies of the Daily Mirror and Daily Record.