Clear Channel announced today the star-studded line-up for the 2014 iHeartRadio Music Festival, the legendary weekend-long concert event that re-writes radio history each year, taking place on September 19 and 20 in Las Vegas. This year's lineup will feature Taylor Swift, Coldplay, Usher, Ariana Grande, Nicki Minaj, Mötley Crüe, Zac Brown Band, One Direction, Ed Sheeran, Paramore, Iggy Azalea, Train, Eric Church, Lorde, Calvin Harris, Bastille, Steve Aoki and more. Highlights of the show will include performances from this year's Macy's iHeartRadio Rising Star winner, Before You Exit, as well as other surprise special guests and never-before-imagined collaborations. The fourth annual event will kick off Friday evening, September 19 at the MGM Grand Garden Arena with host Ryan Seacrest, host and producer of “On Air with Ryan Seacrest,” his market-topping No. 1 nationally syndicated LA morning drive-time show for Clear Channel’s 102.7 KIIS-FM, as well as nationally-syndicated Top 40 radio show.