If you're going to support a charitable cause, don't be ashamed of it. That's basically what Bono told Apple, calling out the technology titans for not promoting its alliance with the U2 frontman's nonprofit (Red) campaign, which fights AIDS.

"Where's the (Red) branding?" Bono asked Apple design head Jony Ive during a talk at Cannes Lions. He pulled out his (Red) iPad cover and pointed to the charity's barely noticeable logo. "Nobody can see that," he said. "This is modesty run amok. This is the Apple way. They're like a religious cult."

Even though (Red) and Apple began a partnership in 2006 with the release of a special bright red iPod Nano, subsequent Apple products supporting (Red) have been less obvious in their affiliation.

"One of the reasons it's such a credit to have Jony Ive on the stage is because Apple is so f---ing annoyingly quiet about the fact they've raised $75 million," Bono told the crowd gathered for his presentation at the annual communications summit. "Nobody knows!"

Ive responded by saying, "We started in 2006 with one (Red) product, a Nano, and now we've got well over half a dozen. It's been really, really special for us."

After blasting Apple, Bono announced that he was looking for new collaborators. "If somebody has one product they make that they could just re-brand next year for (Red), that would be really great outcome for us," he said.

Meanwhile, U2 are apparently still hard at work on their next album, which may or may not come out this year. In the meantime, here's a song they released earlier in the year.

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