The annual awards show takes place on Sunday night with Katy Perry, Ed Sheeran and Bruno Mars all lined up to perform at the Los Angeles bash, where Drake leads the way with 12 nominations.
The Chainsmokers have now become early winners, taking home the prize for Best New Pop Artist. Bruno Mars has been named the Innovator of the Year, while Chance the Rapper is the Best New Hip-Hop Artist.
Zayn Malik's Pillowtalk has won the Best Music Video accolade and 5 Seconds of Summer's Girls Talk Boys from Ghostbusters is the Best Song from a Movie.
Kelsea Ballerini has also been feted as the Best New Country Artist.
The Chainsmokers are also up for a slew of other awards, including Song of the Year and Dance Song of the Year for Closer, Best New Artist, and Producer of the Year.
Other artists who have scooped multiple nominations include Beyonce and Rihanna, who are both up for R&B Artist of the Year, and Ariana Grande, who will compete for Female Artist of the Year against Rihanna, Adele, Selena Gomez, and Sia.
Meanwhile, Drake is up for some of the biggest categories of the night, including Song of the Year for One Dance featuring Wizkid and Kyla Reid, Male Artist of the Year, and Hip-Hop Song of the Year for both One Dance and Controlla.
The fourth iHeartRadio Awards will take place at The Forum. Shawn Mendes, Big Sean and The Chainsmokers will also be performing, with Ryan Seacrest presiding over the evening's events.
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