iHeartRadio Music Festival Featured Surprise Performances By Alicia Keys, Chris Brown & More

The fourth annual iHeartRadio Music Festival hosted by Ryan Seacrest at the MGM Grand Las Vegas wrapped up Saturday night after two days of incredible performances by today's most popular musicians and a number of one-of-a-kind collaborations.

The multi-genre lineup included nearly 40 headliners who entertained concertgoers both on the main stage at the MGM Grand in Las Vegas on the evenings of September 19 and 20 and at the iHeartRadio Music Festival Village on Saturday afternoon.

Performers included Taylor Swift, Coldplay, Usher, Ariana Grande, Nicki Minaj, Motley Crue, Zac Brown Band, One Direction, Ed Sheeran, Paramore, Iggy Azalea, Train, Eric Church, Lorde, Calvin Harris, Bastille, Steve Aoki, 50 Cent, Weezer and more.

The iHeartRadio Music Festival, which debuted four years ago in celebration of the successful iHeartRadio all-in-one digital service, has quickly become one of the most talked about music events of the year. In fact, a recent study sponsored by Eventbrite and Mashwork named the iHeartRadio Music Festival among the top two most buzzed-about music festivals in America.

The Festival is a live representation of the diverse music catalog that fans find and enjoy through the iHeartRadio app, which is ranked the No.

1 digital audio service with over 345 million downloads; the app reached its first 20 million registered users faster than any digital service in Internet history.

The Festival will also return to The CW Network as an exclusive two-night television special on September 29 and 30 from 8:00-10:00 p.m.

The iHeartRadio Music Festival was a dominant social media topic throughout the weekend, and #iHeartRadio continues to trend worldwide with tweets and retweets from fans as well as artists and Festival presenters.

Highlights of the 2014 iHeartRadio Music Festival and Village

Once again, the iHeartRadio Music Festival featured a host of thrilling collaborations and special guest appearances including Steve Aoki and Will.i.am; Ariana Grande and Childish Gambino; Usher and Chris Brown; 50 Cent and G-Unit; Ed Sheeran and Macklemore; and Calvin Harris and John Newman, who closed the 2014 Festival.

Additionally, Jason Derulo, Alicia Keys and Lil John were surprise guest performers.

The Festival drew a large number of celebrity presenters and attendees including iHeartMedia on-air personalities Elvis Duran, Bobby Bones and DJ Prostyle, Pete Wentz, Nick Jonas, Fergie, Chris Pratt, Sophia Bush, Laverne Cox, Nick Cannon, Hilary Duff and more.

Taylor Swift was honored by the Recording Association of America and iHeartRadio to commemorate Big Machine Record's "Shake It Off," which was the fastest certified platinum song in 2014 and the first artist to debut No. 1 on the iHeartRadio chart.

The iHeartRadio Music Festival Village returned to The Lot across from Luxor Hotel & Casino on Saturday afternoon with live performance by Iggy Azalea, Neon Trees, Kacey Musgraves, Childish Gambino, Magic!, The Pretty Reckless, Nico & Vinz, Lil Jon and a surprise collaboration between Fences and Macklemore.

The afternoon event also featured fan zones and interactive experiences by iHeartRadio's brand partners.