Reporter: It was the surprise that stole the show. A surprise that only psy and mc hammer could pull off. But this american music awards was all about one thing, bieber fever! Wow! I feel violated... See More
Reporter: It was the surprise that stole the show. A surprise that only psy and mc hammer could pull off. But this american music awards was all about one thing, bieber fever! Wow! I feel violated right now. Reporter: Justin bieber walked away as the top winner with three prizes, including artist of the year. But not before he walked on stage with mama biebs by his side. I want to thank you for just always believing in me. This is amazing. Reporter: Other proud winners, nicki minaj. ♪ Reporter: Or carly rae jepsen. Who can now call herself favorite new artist. Was that a surprise? Yes, a big surprise. I feel very fortunate. Since I was 7 years old so one day to be here, so this is amazing for me. Reporter: And country stars also had their moment to shine. From best female taylor swift. Have to go and do your own high production performance or whatever. No pressure. Yeah. Reporter: And carrie underwood's -- ♪ Reporter: And luke bryan. To all my fans, I love you! Reporter: To this interpretive dance. To stevie wonder's tribute to awards founder dick clark. ♪ I cherished this night celebrating his life. And we must let his legacy live on. Reporter: It was a show that had everyone on their feet gangnam style. And backstage, we had to get in on the action. Five, six, seven, eight. One, two, three, four -- you got it. You got it. Awesome! Reporter: For "good morning america," cecilia vega, abc news, los angeles. Good stuff there.
This transcript has been automatically generated and may not be 100% accurate.