Good Girls Gone Bad.

Check out our Top 8 Picks: Once Innocent Looking gone Naughty...

CARRIE UNDERWOOD
Jesus took the wheel – and, apparently, drove Underwood to the club, since the country star morphed from American Idol's country sweetheart to booty-shaking sexpot.




AVRIL LAVIGNE
The pop-punker loved sk8er bois and never wore dresses. That was 2002. These days, she's still not wearing many dresses – and sometimes hardly anything at all – as shown on this 2008 Maxim cover.





HILARY DUFF
Six years ago, Duff was a Disney dream as the star of the network's top-rated Lizzie Maguire. Then in the video for "Reach Out," she did just that – reached out for the nekkid body of this hot dude. Cover your eyes, Mickey Mouse




MARIAH CAREY
While married to then-Sony Music honcho Tommy Mottola, Carey was a real vision of loveliness, in girlish curls and little black dresses. Cue her divorce, and she went for really little black dresses, revealing her bikini bod for "Honey."




BRITNEY SPEARS
Sometimes she runs. Sometimes she hides. And sometimes she takes off all her clothes onstage. The former Mouseketeer went from sweet schoolgirl to sparkling stripper in a moment, thrusting her pelvis (and everything else) at the 2000 MTV Video Music Awards. Goodbye, Mickey; hello, Britney!

JESSICA SIMPSON
After always coming in third behind fellow blonde popsters Britney Spears and Christina Aguilera, the vocal virgin showed that you didn't have to have sex to be sexy, writhing with the best of them in the humptastic 2001 video "Irresistible."

CHRISTINA AGUILERA
The teen went from Disney darling to pants-optional in 2002 as X-tina, prompting Tina Fey to joke on Saturday Night Live that the video for Aguilera's song "Dirrty" "gave my TV genital warts."

RIHANNA

In 2005, Rihanna was a fresh-faced teen from Barbados, all sweet smiles and baggy jeans. Just two years later she was out from under that "Umbrella" – showing curves (and then some) – and now she's singing "is you big enough" in her hit "Rude Boy." Something tells us she isn't talking about the dude's weight. Lol...