Outspoken Bono's activism has helped save his career as a rock star in U2 - because he's always so grateful for recording session time with his bandmates. The Where The Streets Have No Name singer has become a leading voice in the war against global poverty, but he insists he could never turn his back on music to become a full-time activist. And he insists the work he does outside U2 helps him appreciate what he has when the group comes together. He tells Rolling Stone magazine, "I've spent a lot of time in these two-dimensional worlds - numbers, values, analysis of statistics - and when I get away from it, being with U2 is such a playground. "It's made me realise how sacred music is. It's a kind of sacrament - like marriage, like friendship. "I'm not sure the other three in the band know this, because they - maybe sensibly - have avoided that other world. They just think they're in U2, and that's great. But I really know how great it is to be in U2. "As it became my job to be in a band, you take for granted that you've got a few hours with your mates in the studio. I don't anymore. It is sanctuary and escape from the material world of casualties, profit and loss, cynicism and hard-bitten victories over your own indifference or somebody else's. "You get into this f**king room and everything seems possible, and I've never really appreciated it more than now... It's this incredible thing. I treasure it."