Keira Knightley has never wanted a penis, but she admits that they sure can come in handy at times.

Speaking with The Guardian about gender and period films, Knightley, 33, quipped, "Almost every character I've played has tried to break out of that image of femininity. That's why I like period films, because it's such an overt cage you put the woman in. That's always something I’ve really identified with. I feel like I sit somewhere else."

She added, "I've never wanted a penis. Apart from to p—s up a tree. Being able to do that standing up: so convenient! You can just whip it out and whatever. But the idea of something so vulnerable swinging between my legs, I think I'm all right without."

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Knightley, who stars in the upcoming period piece "Colette," has previously expressed frustration with how women are perceived and with the pressures and standards placed on women, particularly after childbirth.

In a graphic essay in October, Knightley slammed Kate Middleton for her picture-perfect public appearances after the births of her children, writing, "Seven hours after your fight with life and death, seven hours after your body breaks open, and bloody, screaming life comes out. Don't show. Don't tell. Stand there with your girl and be shot by a pack of male photographers. This stuff is easy. It happens every day. What's the big deal? So does death, you s—t heads, but you don't have to pretend that's easy."

Last week, Knightley confessed that she suffered a mental breakdown when she was just 22 years old due to the pressures of fame.

She also suffered from post-traumatic stress disorder, leading her to almost leave show business entirely.