Jenn Rogien, the costume designer for HBO's Girls, recently picked up a side job as the "style and fit expert" for Aerie, American Eagle's underwear label. The brand introduced her today with an e-mail blast to their customers and a video of Rogien giving underwear advice, specifically on bras. Originally an assistant buyer at Saks, Rogien got into costume design when she went back to school at Parsons. "My signatures are fit and naturalism," she says, advising everyone to make sure their bras are big enough. And we believe her. After all, if anything would qualify someone as an expert in "naturalistic" undress, it would be working on the Girls set.