They’ve got hit records, millions of fans, and the kind of success most musicians only dream of -- and they can’t even buy a glass of champagne to celebrate their success. Welcome to Billboard.com’s 2011 installment of 21 Under 21, our annual ranking of music’s most powerful minors.

From bubbly boy bands to white-hot producers, sexy K-Pop princesses to pint-sized Reggeaton powerhouses, rising hip-hop stars to international pop icons, these are the fresh faces whose careers will continue to pack the biggest punches over the next 12 months. Get used to this crew, because they’re all just getting started.

No. 21: Miley Cyrus

Birthdate: November 23, 1992 (age 18)

Why She’s Hot: Miley’s had quite the year — some ups, some downs — but despite lackluster sales of her third studio album and that whole Salvia snafu, Ms. Cyrus is still a teen force to be reckoned with. Miley kicked off 2011 by hosting “Saturday Night Live” and bringing her sexy new image to fans from South America to Australia on her successful Gypsy Heart Tour. Her live show earnings, as well as revenue from album sales, Disney’s “Hannah Montana” franchise, and feature films such as “The Last Song,” helped to bring her in at No. 18 on Forbes’ Hollywood Highest Earners List in at the tail of 2010.

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