Published Saturday, 07 July 2012
The band shot to fame following the release of Lungs on 6 July 2009 and on Friday they marked the milestone at the annual event.
Singer Florence Welch made reference to the anniversary with a rare live performance of Between Two Lungs, a track from the album, as a special treat for fans.
She told the crowd: "We weren't going to play this song, but since it's a special day..."
Reunited rockers the Stone Roses are due to headline the festival on Saturday and Kasabian will close the event on Sunday.