Lena Dunham Instagrammed a pic of her new Marie Claire UK September issue cover, thanking "sweet Erdem" for making women of all sizes look gawgeous. {Marie Claire UK and Instagram via @lenadunham} You can add horseback riding to Mary-Kate Olsen's list of hobbies: The CFDA-winning designer was spotted at the Hampton Classic this weekend, accepting an award for her horse Marvelous. {NY Post} We were so busy fawning over Michelle Obama's perfect Tracy Reese dress yesterday that we failed to notice... her new highlights! {Glamour} Stella McCartney and Goop collaborate on a line of... we don't know exactly what yet. But here are some pretty good guesses. {Telegraph}