Jessica Simpson and Hillary Duff could take some lessons from supermodel and Victoria's Secret staple Alessandra Ambrosio as she spent her time exercising. Here she is leaving yoga class in Brentwood and she's looking as if she were back to shape, or as if she didn't give birth at all. How they do it? Answer: Sheer determination. That's what. More pictures of Alessandra Ambrosio in the gallery below: