21 Under 21: Willow Smith (2011)
21 Under 21: Willow Smith (2011)

No. 14. Willow Smith

Birthdate: Oct. 31, 2000 (age 10)

Rank Last Year: 7

Why She's Hot: Plenty of youngsters have scored to 40 hits, but how many can say they ruled the charts before their 10th birthday? Willow's "Whip My Hair" was an almost overnight sensation that rose to No. 11 on the Billboard Hot 100 and made the singer and actress - who made her big-screen debut alongside her famous daddy in 2007's "I Am Legend" -- a true double-threat at only age 9. The daughter of musician/actor Will Smith and actress Jada Pinkett Smith, Willow is no stranger to the limelight and has already been active in charitable pursuits alongside her budding career in entertainment. After debuting her second single "21st Century Girl" on "Oprah" earlier this year, the anticipation for her forthcoming debut album -(set to be released by Roc Nation later this year) continues to grow a year and counting after "Whip My Hair."

NEXT: Cody Simpson