Pharrell set for 1st iHeartRadio Music Awards

What color hat will Pharrell wear this time?

The "Happy" singer is set to perform at the first iHeartRadio Music Awards on Thursday night at the Shrine Auditorium in Los Angeles. Rihanna, Diddy and Jennifer Lopez will attend, and A-list acts from Drake to Blake Shelton will hit the stage.

The three-hour, fan-voted show will air live on NBC starting at 8 p.m. Eastern.

While there are trophies, the performances will be the night's main highlight. Kendrick Lamar, Ariana Grande, Shakira, Ed Sheeran and Arcade Fire are also part of the jam-packed line-up, which will include performances from L.A. venues including the Shrine Auditorium, the Roxy and the Hotel Cafe.

Rihanna, Justin Timberlake, Maroon 5, Macklemore & Ryan Lewis and Imagine Dragons will compete for artist of the year.