Fifth Harmony vowed to make their fans "proud" with their new music as they picked up the Best Fan Army gong at the 2017 iHeartRadio Music Awards.

Fifth Harmony

Fifth Harmony

The 'That's My Girl' girl group's fanbase - known as Harmonizers - beat off stiff competition from the likes of Beyonce's Beyhive, Justin Bieber's Beliebers and Rihanna's Navy at the star-studded bash at The Forum in Inglewood, California on Sunday (05.03.17) taking home the prestigious gong.

In their acceptance speech, Ally Brooke, 23 - who is joined by Lauren Jauregui and Normani Kordei and Dinah Jane in the pop band - said: "Thank you so much. Wow. This is truly amazing. Fans, you guys are truly a force to be reckoned with.

"We love you too. Thank you for bringing so much joy and kindness and love to our world. We wouldn't be the same without you. We thank God for you. This is for you, so thank you so much."

And Dinah, 19, added: "Y'all have been working so hard and we have been working just as hard.

"We are sure to make you all so proud. Y'all stay tuned for new music."

Other big winners on the night included chart-topping electronic duo The Chainsmokers - comprised of Alex Pall and Drew Taggart - who took home three gongs for Best New Artist, Dance Song of the Year for 'Closer' featuring Halsey and Best New Pop Artist.

Bruno Mars picked up the Innovator Award and twenty one pilots took home Alternative Rock Song of the Year for 'Heathens' and Alternative Rock Artist of the Year.

Highlights from the evening included Justin Timberlake dedicating his Song of the Year Award to the LGBT community.

Whilst collecting his award for Song of the Year for 'Can't Stop The Feeling', he said: "I wrote this song because I wanted it to be about inclusion, about being together.

"If you are black or you are brown or you are gay or you are lesbian or you are trans -- or maybe you're just a sissy singing boy from Tennessee. Anyone that is treating you unkindly, it is only because they are afraid or they have been taught to be afraid of how important you are because being different means you make the difference. So f***'em."

And though he couldn't attend, due to being in Paris for Fashion Week, Zayn appeared in a video message with his girlfriend and co-star in his video for 'Pillow Talk', Gigi Hadid, to accept the Best Music Video accolade.

In the short clip, he said: "I'm currently in Paris. Sorry I can't be there.

"A little birdie told me that I've actually won an award, so thank you very much. I'm very honored. To everyone that voted, it means a lot, and my costar's actually sitting next to me right here, so she's gonna say hello as well."

The 2017 iHeartRadio Music are as follows:

Innovator Award - Bruno Mars

Song of the Year: 'Can't Stop the Feeling' - Justin Timberlake

Best New Artist: The Chainsmokers

Alternative Rock Song of the Year:

'Heathens' - twenty one pilots

Alternative Rock Artist of the Year:

twenty one pilots

Rock Song of the Year:

'Bang Bang' - Green Day

Rock Artist of the Year: Disturbed

Country Artist of the Year: Thomas Rhett

Dance Song of the Year:

'Closer' The Chainsmokers featuring Halsey

R&B Song of the Year: 'Work' - Rihanna featuring Drake

Best New Rock/Alternative Rock Artist:

The Strumbellas

Best New Country Artist: Kelsea Ballerini

Best New Hip-Hop Artist: Chance the Rapper

Best New Latin Artist: CNCO

Best New R&B Artist: Bryson Tiller

Best New Regional Mexican Artist: Joss Favela

Best New Pop Artist: The Chainsmokers

Best Lyrics: 'Love Yourself' - Justin Bieber

Best Song from a Movie - 'Girls Talk Boys' - 5 Seconds of Summer ('Ghostbusters')

Best Music Video - 'Pillow Talk' - Zayn Malik

Best Fan Army presented by Taco Bell - Fifth Harmony - Harmonizers

Best Tour - Coldplay