The aim was to raise awareness about climate change. 70,000 turned out at Wembley Stadium to watch the likes of Madonna, The Foo Fighters and Keane on stage. We catch some of the stars behind the scenes.
Will.i.am from Black Eyed Peas is trying to help: "I crushed my hummer, gettin' solar panels put on my studio in my home." Fergie's also doing her bit: "I want everyone to know I'm putting my hummer up for sale."