No. 15. Greyson Chance
Why He's Hot: Call him the thinking man's Justin Bieber. Armed with classical training, a way-beyond-his-years voice and a knack for emotional songwriting, Greyson Chance has built upon the overnight success he gained when his cover of Lady Gaga's "Paparazzi" earned 43 million YouTube views. After touring with Cody Simpson earlier this year, Chance released "Hold On 'Til the Night," a debut album inspired by Snow Patrol and Coldplay, in August. Next up for Chance is a massive touring block, where he'll bring singles like "Waiting Outside the Lines" (9 million YouTube views) and "Unfriend You" (6 million YouTube views) to even bigger audiences.