Metallica's Lars Ulrich has praised U2 for giving away their album on iTunes.

The drummer has come out in favour of U2's controversial decision to make their new album, 'Songs Of Innocence', an automatic and free download for over 500 million Apple users, calling it ''immensely'' inspirational and even compared the record's release to ''reinventing the wheel''.

Talking to Billboard, Lars said: ''It's 2014 and anybody who thinks outside the box, or attempts in any way, shape or form, to break the status quo in the world of music, should be applauded. To me, it's not about whether the endeavour is a success or not. It's the fact that they have the balls and the foresight to throw something radical at us.''

U2 frontman Bono recently insisted the giveaway was ''punk rock'' and he was happy to ''shake things up'' in the music industry with the release.

He said: ''That's always been the way. It was the same on our first album. That was kind of why you got into a band, to stir things up and annoy people. That's the whole punk rock thing... the only thing that could have gone wrong would have been being ignored.''

The 'One' rocker then pointed out over 38 million people listened to the record within a week of release, so he feels fulfilled by the decision.

He added: ''If you're a songwriter, if you're in a band, that's all you can ask for. Whether they take them to their heart is something else.''

Apple came under fire once the record had been automatically downloaded onto iTunes accounts on September 9.

Many angered iTunes users contacted the company to try and delete the unwanted album, which originally could not be removed from the device. Since then, Apple have had to release a tool which allows customers to remove the content.