Selena Gomez, Shailene Woodley, Tyler Posey and 5 Seconds of Summer
Best: Demi Lovato
Every awards show needs an energetic number to kick things off. It also helps if that number is good. Enter Demi Lovato who (mostly) sang her upbeat anthem "Really Don't Care" with a good number of backup dancers and friends on stage. Lovato has pipes and at 21 she's got the stage presence of a 20-year vet. She's now a prop's pro and was the perfect artist (outside of Ariana Grande who didn't perform) to get the audience of mostly teenage girls in a frenzy. It worked.