Stevie Wonder, Green Day, The Killers, The Lumineers and The Chainsmokers will perform at the Global Citizen Festival, a free annual event in iconic Central Park in New York. Artists Pharrell Williams, Big Sean, Andra Day and Alessia Cara will participate as guests at the Sept. 23 concerts. MSNBC and Comcast NBCUniversal will broadcast the entire day simultaneously and live on MSNBC and MSNBC.com. Some of the singers will do double, as the Global Citizen Festival coincides with the iHeartRadio Music Festival. Big Sean, for example, will perform at both events in one night. Those interested in attending the Central Park event can get their tickets for free by joining the globalcitizenfestival.com movement.