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Host J. Lo opened the show by dancing to the year's biggest hits.
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Selena Gomez performed "Same Old Love" from her most recent album, Revival.
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5 Seconds of Summer
The Aussie pop-punk band ran through "Hey Everybody," off their second album, Sounds Good Feels Good, which debuted at No. 1 this month.
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Carrie Underwood gave a moving performance of "Heartbeat," and won Favorite Female Country Artist.
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With two back-up dancers and a whole bunch of cabaret style, Demi Lovato sang the title track from Confident.
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Charlie Puth and Meghan Trainor
Charlie Puth and Meghan Trainor came together to sing "Marvin Gaye" and "Like I'm Gonna Lose You" before ending their performance with the smooch of the night.
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Ariana Grande performed "Focus" for the first time on a live broadcast.
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Before taking home the Favorite Artist of the Year award, One Direction brought the single "Perfect" to life.
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Nick Jonas performed a medley of hits including "Levels," "Chains," and "Jealous," backed by a full choir.
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Alicia Silverstone and Jeremy Sisto of Clueless introduced Gwen Stefani, who gave an emotional performance of her latest single, "Used To Love You."
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Walk The Moon
"Shut up and dance," Walk the Moon sang to the crowd. And so they did.
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After raking in awards for Favorite Soul/R&B Album and Favorite Male Soul/ R&B Artist, The Weeknd turned up the pyrotechnics to sing "The Hills."
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With only a few weeks until they drop their next album, Coldplay took the stage to sing its first single, "Adventure of a Lifetime."
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Macklemore and Leon Bridges
Macklemore debuted a new track, which explores oxy addiction in America. Called "Kevin," it features vocals from powerhouse Leon Bridges.
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Alanis Morissette and Demi Lovato
Demi Lovato and Alanis Morissette celebrated the 20th anniversary of Jagged Little Pill with a huge performance of the album's hit single, "You Oughta Know."
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Celine Dion gave an emotional tribute the victims of the Paris attacks by singing a moving cover of Edith Piaf’s “Hymne a L’amour.”
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Luke Bryan and Karen Fairchild
Country stars Luke Bryan and Karen Fairchild performed "Home Alone Tonight." Bryan also picked up an award for Favorite Male Country Artist.
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Los Angeles' Microsoft Theater literally rained down on Justin Bieber as he performed three songs from his new album Purpose. No one was... "sorry."