Oh, and many a prize was won.
No surprise here: Taylor Swift took home the night's top honor, artist of the year, after Cyrus hit the stage to perform "Wrecking Ball."
"I'm really out of breath. I was really going hard with the 'Wrecking Ball' thing," Swift, who also collected wins for favorite country album, favorite female pop/rock artist and favorite country female artist, told the audience.
"This validates that if you voted for this, that we are heartbroken the same way and we are in love the same way and we're happy the same way," she added. "I'm 23 and I have no idea what's going to happen to me in my life."
More big winnersBefore taking the stage at Los Angeles's Nokia Theatre L.A. Live, Timberlake kicked off the fan-voted awards show with a win for favorite pop/rock male artist, later scooping up victories in the soul/R&B artist and soul/R&B album categories.
"You guys have a great night," he quipped in his latter acceptance speech. "Sunday in L.A. – who knows?"
Also winning big: Ariana Grande (new artist of the year), Marc Anthony (favorite Latin artist) and One Direction (favorite pop/rock band/duo/group and favorite pop/rock album).
But, despite Swift's sparkly dress and mega wins, it was arguably Rihanna who shone the brightest (like the diamonds she sang about!).
Not only did she take home honors for favorite soul/R&B female artist, but she was also bestowed the first-ever Icon Award, presented by her mom.
She recalled the days when her "annoying little husky man voice" would earn anything but accolades from her mother – and the neighbors. "I annoyed everyone," she told the audience, later nodding to her fans, "You keep me driven. You keep this thing special."