Why does Julia Roberts walk like a penguin?

It can't be a coincidence that she walks like a person with one leg shorter than the other. She hobbles from side to side when she walks. It is especially noticeable in films where there are long shots of her walking alone toward the camera. You would think that someone would have told her to walk like a lady. Her strut is repulsive. Way worse than Meg Ryan's. Is there something medically wrong with her?