November 18, 2003 - Mark Mainz/Getty Images Entertainment more pics like this »
5. Teen Sensation

Britney became famous as a teen, so at the ripe age of 22 (as seen here at TRL studios in 2004) she'd already sold over 37 million albums. She is listed in the Guinness World Records as having the "best-selling album by a teenage solo artist" for her debut album ...Baby One More Time.