The most dramatic celebrity hair makeovers of 2011
( InStyle.com )  -- Stars like Katy Perry and Jennifer Lawrence changed up their hair color and length in 2011 and achieved dramatic results.  See the most memorable hair transformations of the year.  Blake Lively  The "Gossip Girl" star went auburn in late April for her role in the  upcoming film "Hick." In June, Lively lightened her strands back to  blond.  "I love it," she told InStyle.com on her ever-changing 'do. "When I  play a character I love to completely transform, and changing up my hair  color is a way I feel like I can disappear behind them."  Katy Perry  Katy Perry went back to her blond roots in July, then revealed a new lavender hue at the VMAs in August.  "It was such an exciting challenge to custom-create Katy's color for  the VMAs," her colorist Rita Hazan said. "She is always willing to take  risks to achieve a groundbreaking look."  InStyle.com: See all the hottest celebrity hair makeovers of 2011 ...