The (500) Days of Summer star took to Twitter recently to share the letter with her fans which she wrote when she was just 17.
The 31-year-old self-confessed 'young feminist' wrote, 'Why would you want to limit the spectrum of beauty to an 'ideal' when you, as a popular women's magazine, have the opportunity to expand it? I don't think any woman should have to feel as if she needs to shove herself into an 'ideal' to be beautiful.
'Beauty should be something that is celebrated and something that is enjoyable, not something that people should feel uncomfortable about achieving.
'Most of the women, and certainly most of the adolescent girls, in the United States do not feel completely secure with themselves, especially with their appearance; is insecurity something you want to advocate?
'As American women, we don't need discouragement, but inspiration.'
The actress then tweeted, 'No hard feelings Vogue magazine, love your mag! I was a feisty 17.'