U2 were forced to pulled out of a planned trip to help Nelson Mandela celebrate his 90th birthday party -- to concentrate on their latest album.
The supergroup were due to join a host of other stars at London's Hyde Park on Friday for a special concert.
But the group backed out at the last minute -- with Bono and the Edge sending a video message instead.
The millionaire rockers are holed up in their Hanover Quay studios in Dublin putting the final touches to their new album which is expected to be released in October.
A source close to the band said they were bitterly disappointed they couldn't make the party.
"The band have always been supporters of the anti-apartheid movements and became personal friends with Mr. Mandela. They wanted to go but are simply snowed under," said the source.