America proved its Bieber Fever was strong: The teen singer dominated the American Music Awards on Sunday night.
Bieber's wins included the show's top award, artist of the year. His mom joined him onstage as he collected the trophy, beating out Rihanna, Maroon 5, Katy Perry and Drake.
"I wanted to thank you for always believing in me," Bieber said, looking to his mom.
The 18-year-old also won the honour in 2010. He said it's "hard growing up with everyone watching me" and asked that people continue to believe in him.
Bieber and Nicki Minaj performed together — and separately — at the AMAs and were both multiple winners.
But another collaboration was the night's most colorful performance: Korean rapper PSY and MC Hammer. Hammer joined the buzzed-about pop star for his viral hit Gangnam Style. PSY rocked traditional "Hammer" pants as they danced to his jam and to Hammer's Too Legit to Quit.
Bieber won favourite pop/rock male artist in the first award handed out at Sunday's show and gave a shout-out to those who didn't think he would last on the music scene.
"I want to say this is for all the haters who thought I was just here for one or two years. I feel like I'm going to be here for a very long time," he said.
He also won favourite pop/rock album for Believe. He gave a stripped down, acoustic performance of As Long As You Love Me, then transitioned to the dance-heavy Beauty and a Beat, where Minaj joined him onstage, grinding with the teen for a few seconds.
Minaj, who wore three different wigs and four outfits throughout the night, repeated her AMAs wins from last year, picking up trophies for favourite rap/hip-hop artists and album for Pink Friday: Roman Reloaded.
She was in an all-white get-up, including fur coat and pink hair when she performed her new song Freedom. The scene was ghostly and snowy, as a choir — also in white — joined her onstage. One background singer stole the performance, belting semi-high notes as Minaj looked on.
As Bieber won his second award, he was kissed on the neck by Jenny McCarthy, who presented the award.
"Wow. I feel violated right now," he said, laughing.
"I did grab his butt," McCarthy said backstage. "I couldn't help it. He was just so delicious. So little. I wanted to tear his head off and eat it."
Bieber's red and black outfit seemed to be the night's theme, as Taylor Swift and Usher wore similar ensembles.
Usher kicked off the three-hour show with green laser lights beaming onstage as he performed a medley of songs, including Numb, Climax and Can't Stop, Won't Stop, which featured a smoky floor and a number of backup dancers, as Usher jammed in all black, with the exception of his red shoes. He won favourite soul/R&B male artist.
Swift won her fifth consecutive award for favourite country female artist.
"This is unreal. I want to thank the fans. You guys are the ones who voted on this," she said.
Swift gave a masquerade-themed performance of the pop song I Knew You Were Trouble. She sang onstage in a light dress while dancers wore mostly black. But then she changed into a red corset and black skirt, matching their dark mood. She even danced and sang on the floor as lights flickered throughout the performance.
Dick Clark, who created the AMAs, was remembered by Ryan Seacrest and an upbeat performance by Stevie Wonder.
Carly Rae Jepsen, who performed early in the night, won favourite new artist.
"I am floored. Wow," she said, thanking Bieber and his manager, Scooter Braun.
Party girl Ke$ha was glammed up on the red carpet, rocking long, flowy blonde hair and a light pink dress. She switched to her normal attire when she performed her hit single Die Young. It was tribal, with shirtless dancers in skin-tight pants, silver hair and skeleton-painted faces, who also played the drums. Ke$ha was pants-less, rocking knee-high boots and rolling on the floor as she finished up the song.
Christina Aguilera, sporting a blonde bob and a purple dress that matched her eyeshadow, performed a medley of material from her new album and joined Pitbull onstage.
Kelly Clarkson also hit the stage, making a nod to her American Idol roots with a number on her dress and three judges looking on as she sang Miss Independent. Then she went into Since U Been Gone, Stronger and Catch My Breath.
Fellow Idol winner Carrie Underwood won best favourite country album, also performed, hitting the right notes during her performance of Two Black Cadillacs. Luke Bryan won favourite country male artist and Lady Antebellum favourite country group.
American Music Awards nominees were selected based on sales and airplay, and fans chose the winners by voting online.
"What makes the American Music Awards special is the fans choose the winning artists," said Chester Bennington of Linkin Park, who won favourite artist alternative rock and performed Burn It Down, as Brandy sang along and Gwen Stefani, Usher and Phillip Phillips bobbed their heads.
David Guetta won the show's first-ever electronic dance music award. Non-televised awards went to Katy Perry for pop/rock female artist, Beyonce for soul/R&B female artist, Adele for adult contemporary artist and Shakira for Latin artist.
Along with Rihanna, Minaj was the top nominee with four nominations.