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Iconic rapper Jay-Z says he may be to blame for the delay of U2's long-promised studio album, 'Songs of Ascent.' Although the disc, which was first expected in 2010, could still be on target for release when the Irish rock giants' North American tour gets underway in May, time is running out to execute a proper publicity campaign.

"One night I ran into Bono and he told me he'd read an interview I'd done," Jay-Z tells The Sun. "The writer had asked me about a U2 record ['No Line on the Horizon'] that had just been released and I said something about the pressure a group like that must be under just to meet their own standards.

"[Bono] said the quote had really gotten to him and he decided to go back to the studio, even though the album was already done, and keep reworking it 'til he thought it was as good as it could possibly be," said Jay-Z, who opened a run of shows in Australia and New Zealand for U2 late last year.

"I was surprised that at that point in his career he still got anxious about his work."