Vampire Weekend and Foster the People will also headline the Delaware festival's 70+ band lineup
The festival's second year will run June 21-23 at Delaware's the Woodlands of Dover International Speedway.
Other highlights from the summer festival include the Lumineers, Grizzly Bear, Yeah Yeah Yeahs and MGMT. The festival's hip-hop offerings will include Public Enemy, Kendrick Lamar, Azealia Banks and Action Bronson, with Lady Gaga collaborator Zedd and Calvin Harris leading the electronic acts.
Amanda Palmer, Matt and Kim, Ellie Goulding, the Walkmen, Alabama Shakes, the Avett Brothers, Purity Ring, Japandroids and newcomers such as Haim, Blondfire and Atlas Genius are also on the three-day, four-stage event's bill.
Tickets will be available Feb. 21 at noon EST via FireflyFestival.com. As with 2012's inaugural festival, Firefly will team with the St. Jude Children's Research Hospital to create charity opportunities, as well as welcoming back Dogfish Head Brewery and other returning attractions.