I'm digging her casual grey cotton dress while out & about in Los Angeles today. Somehow she has a way of making even the most simple items look chic. Grey is an important color this fall, so you can take a dress like this and add a pair of boots (ankle or tall, both will do!) - personally I love the idea of throwing on a short black leather biker jacket, when the weather starts to turn.

Here are some terrific casual grey dresses to help you Get The Look of Sienna Miller!