Taylor Momsen + Dakota Fanning in ‘The Runaways’ – Celebrity Doppelgangers

Who would have thought that one day we would see adorable child stars Taylor Momsen and Dakota Fanning wearing lingerie on the street and embracing the world of sex, drugs and rock n' roll. But that's just what happened.

Momsen was the cute-as-pie Cindy Lou Who in the 2000 film 'The Grinch,' and she later played Jenny Humphrey on the CW hit show 'Gossip Girl.' Then she quit the series and took a strange turn, donning raccoon eye-makeup and refusing to wear pants as she pursued a music career -- and this was well before her 18th birthday. Now almost 20, Momsen and her band the Pretty Reckless will release their second album this year.

Fanning shed her child star image in the 2010 film 'The Runaways,' which told the story of the real life all-girl rock group fronted by Cherie Currie (played by Fanning) and guitarist Joan Jett (Kristen Stewart). And with four movies now in post-production, it's clear Dakota, 19, managed to make the difficult leap from kid actor to grown-up film star with success.