Florence and the Machine, Vampire Weekend and Belle & Sebastian have been confirmed to top the bill at the Suffolk bash, which is held at the Henham Park Estate from July 15 to July 18.
Other acts so far announced include The xx, Empire Of The Sun and Grizzly Bear.
The National, The Horrors, Rodrigo Y Gabriela, The Maccabees and Charlotte Gainsbourg will also appear at the festival.
Full weekend tickets cost £155. Day tickets are £65.