Firefly Music Festival has announced their initial lineup, minus one headliner. The annual festival held in Dover, DE will see performances from Kings of Leon, The Killers, and a mystery, yet-to-be-revealed headliner. Other performers include Morrissey, Snoop Dogg, Foster the People, Zedd, Modest Mouse, Bastille, Empire of the Sun, Hozier, Kid Cudi, Steve Aoki, Sublime with Rome, Spoon, Cage the Elephant, AWOLNation, and The Kooks.

The festival is held from June 18-21, with tickets currently on sale via the Firefly official website. Check out the full lineup below: