Coldplay may have their heads in the clouds — because their new album, X&Y, has topped the Billboard albums chart for two weeks running, selling more than 1 million copies, and its first single, "Speed of Sound," is a massive radio hit — but, as always, they've still got their feet firmly planted on the ground.

For the past few years, frontman Chris Martin has been a walking signboard for various political causes, from handgun control to ending Third World poverty (see "Coldplay: The Quiet Revolution"), all sentiments that he claims the band shares. And though Martin has caught flack for the stances he takes, he's not going to stop anytime soon.

"Anything I say about fair trade, something that we all believe as a band, it's just my job as the frontman to say it," Martin said. "So I always have the strength of knowledge that when I'm talking about it, I'm talking for all four of us, so that makes it much easier to deal with any cynicism or criticism.

"And it's kind of curious to me that at times I'm in a position where people are asking me to explain myself for sort of going out there," he continued. "I can understand the point of view that you think, 'Well, why is a singer talking about fair trade?' But I can't understand if it's actually skeptical about the issue itself. If people want to be critical of us for talking about it, that's fair enough, as long as they don't take umbrage with the actual issue."

And Coldplay will continue their humanitarian ways at this weekend's Live 8 concert in Hyde Park, London — just one of nine international cities hosting concerts on July 2 to raise awareness

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about poverty in the developing word (see "Live 8 Concerts Will Air On MTV, VH1"). Artists playing at the shows include Destiny's Child, Audioslave, the Dave Matthews Band, Mötley Crüe and Good Charlotte. In London, Coldplay will share the stage with a host of artists, including the re-formed Pink Floyd, Velvet Revolver, REM and their heroes U2.

"U2 is like the top of Mt. Everest for us or for any band," Martin enthused.

But being on the same bill as the band they grew up idolizing isn't the biggest thrill for Coldplay. They're more excited to take part in the biggest goodwill endeavor of their lives.

"We're not talking about fair trade because we are trying to be cool or unique. We're doing it because we've been to places where the trade policy is screwing the country over: in Ghana or in Haiti or Mexico or Mozambique, I mean the list goes on and on and on," Martin said. "So to get the message out there to people who might not be aware is the most important thing of all."