Coldplay are a critically acclaimed Grammy award winning English rock band. Formed in 1998 in London, Coldplay achieved worldwide fame with their 2000 single "Yellow", followed by the success of their debut album, Parachutes. The group comprises vocalist/pianist Chris Martin, guitarist Jonny Buckland, bassist Guy Berryman and drummer Will Champion. Coldplay have been one of the most successful acts of the new millennium, selling over 30 million albums to date.[citation needed] Coldplay's early material was compared to acts such as Jeff Buckley and Radiohead,[1] while also drawing comparisons to U2[2] and Travis. Since the release of Parachutes, Coldplay has also drawn influence from other sources, including Echo and the Bunnymen[3] and George Harrison[4] on A Rush of Blood to the Head (2002) and Johnny Cash and Kraftwerk for X&Y (2005).[5] Coldplay has been an active supporter of various social and political causes, such as Oxfam's Make Trade Fair campaign and Amnesty International. The group has also performed at various charity projects such as Band Aid 20, Live 8, and the Teenage Cancer Trust.[6] As of December 2006, the band is working on their fourth studio album, produced by Brian Eno and expected to likely be released in early 2008.