21 Under 21: Cody Simpson
21 Under 21: Cody Simpson

No. 20: Cody Simpson

Birthday: January 11, 1997 (age 13)

Why He's Hot: If you're looking for the next teen pop heartthrob with a great haircut and international cache, Cody Simpson's your man. The 13-year-old Australian joined the fray this summer with "iYiYiYi," an ultra-catchy debut single featuring Flo Rida, and his debut album for Atlantic Records is now in the works. Comparisons to Justin Bieber are inevitable, but Simpson doesn't mind following in said star's footsteps: "Being compared to someone who's already been really successful is flattering," the singer recently told Radio Disney. How's that for showbiz smarts?

Video Below: Cody's take on Ben Harper's "Steal My Kisses" for Billboard's Mashup Mondays

Next: Nikki Yanofsky