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.