Mirren, 67, was a nominee for Best Actress for her performance in "Hitchcock." She lost out to "Amour" star Emmanuelle Riva.
"I saw it on 'America's Next Top Model,' so I decided to have a go," People.com said Mirren told reporters about her new hairdo just before the British Academy of Film and Television Arts awards ceremony began.
"I know I won't win tonight, but I'm going to have lots of fun and celebrate anyway."
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