Best Dressed at the Screening of 'The September Issue'. Celebs show their best fashion at the screen of the 'The September Issue' from Sienna Miller wearing a flirty blue bubble dress to Renee Zellweger wearing a gorgeous brunt orange and gold dress that was stunning. Anna Wintour of course showed her best style while Donna Karan wore a black classic jumpsuit. Check out the best fashion below.





