The 36-year-old actress, who is in a relationship with actor Joshua Jackson, admits her old outlook was "stupid," reported Female First.
"When I was younger, being beautiful meant being skinny; I was a model, so you can imagine how hard it was to stay in shape.
"But when I turned 30, I realised how stupid I was for believing that. I think you're beautiful when you're smart and beauty is something you need to achieve.