This is a Roger Vivier Cut Up bag. It can be customized with letters. J A stand of course for Jessica Alba. Here is a pic of the bag, customized with the name 'Ines' (which stands for Ines de la Fressange, former Chanel model and Vivier ambassador).
Also, a bit off-topic: but Alba is taking a while to get to her pre-preg body. I wonder if she'll be able to pull it off....