Good Girls Gone Bad

Miley Cyrus isn't the first pop star to show her naughty side – check out how Britney, Christina, Rihanna and more stars went from PG to R-rated

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.