Razorlight were among the first bands to perform at the London leg of Live Earth at Wembley Stadium.
The Red Hot Chili Peppers performed four songs, including By The Way and Dani California.
Comedian Eddie Izzard arrived on stage to introduce some of the acts.
Fergie and her Black Eyed Peas group were among a number of US acts to grace the London stage.
More than 60,000 fans crowded into the new Wembley Stadium for a whole day of live music.
Kasabian's Tom Meighan got the crowd at Wembley up and dancing, urging people to "save the polar bears".
US singer John Legend played to the Wembley crowd - who were enjoying a rare day of sunshine.
Liam Gallagher was spotted in the audience with one of his children.
Spinal Tap reformed for the Live Earth gig - and were no less flamboyant than they were in their 1980s heyday.
US rap group The Beastie Boys performed Intergalactic and Sabotage during their set.
Madonna was joined on stage by gypsy band Gogol Bordello for an energetic rendition of La Isla Bonita.