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
Dianna Agron
The "Glee" actress cut her blond waves into an edgy shag