Cody Simpson: 21 Under 21 (2012)
Cody Simpson: 21 Under 21 (2012)

No. 12: Cody Simpson

Last Year's Rank: 13

Birthdate: January 11, 1997 (Age 15)

Why He's Hot: At age 15, Australian pop star Cody Simpson is already a veteran recording artist and live performer, having spent the past three years bewitching young ladies while releasing collaborations with artists like Flo Rida and T-Pain. After issuing three EPs -- the first of which, 2010's "4U," featured the breakout hit "iYiYi" -- Simpson will finally release his debut album, "Paradise," in October through Atlantic Records (the disc has been promoted through the interactive film "Finding Cody"). Meanwhile, theyoung star is preparing to join Justin Bieber and Carly Rae Jepsen on select arena tour dates before headlining in Europe and the U.S. After years of bubbling under, Codymania may finally be ready to spill over.

Video Below: Cody Simpson 's "Wish You Were Here" feat. Becky G

Next: Jackie Evancho