Media playback is unsupported on your device Media caption Bono says sorry to fans - video from Facebook

U2 frontman Bono has said sorry after their latest album was automatically added to the libraries of all iTunes users around the world.

Speaking in a session on Facebook, the star said the move was a "drop of megalomania, a touch of generosity".

In response to a questioner who told him it was "rude" to impose their music upon everyone, Bono said: "Oops, I'm sorry about that."

Apple later released a one-click tool enabling iTunes customers to remove it.

Some users complained that the 11-track Songs of Innocence had been added to their music library without permission and that it was not clear how to delete it.

Image copyright Getty Images Image caption The band appeared with Apple chief executive Tim Cook in September to launch the album

The questioner on the Facebook session said: "Can you please never release an album on iTunes that automatically downloads to peoples playlists ever again? It's really rude."

Bono replied: "I had this beautiful idea and we got carried away with ourselves. Artists are prone to that kind of thing.

"A drop of megalomania, a touch of generosity, a dash of self-promotion and deep fear that these songs that we poured our life into over the last few years mightn't be heard.

"There's a lot of noise out there. I guess we got a little noisy ourselves to get through it," he said.

The music was made available for free to more than 500 million iTunes customers in 119 countries last month. It has been reported that around 5% of those have downloaded U2's latest opus.

At the time, Bono acknowledged that not everyone would appreciate the move.

"For the people out there who have no interest in checking us out, look at it this way… the blood, sweat and tears of some Irish guys are in your junk mail," he wrote on the band's website.

Bono's apology comes after rock legend Iggy Pop criticised the band for "giving away music before it can flop, in an effort to stay huge".

The physical version of Songs of Innocence, including a six-track acoustic session, went on sale on Monday.

The Irish band's last album, No Line on the Horizon, released five years ago, topped the UK album chart and went on to sell five million copies.