Sienna Miller hit the red carpet at the ceremony for the 2017 Breakthrough Prize on Sunday, an in doing so she reminded us exactly why she is one of our enduring style icons. Sienna, who came in at No. 1 in our list of the best dressed Brits last year, wore a beautifully detailed long-sleeved pink gown with floral panels and lace overlays. This year has been as stylish as ever for Sienna, who topped off a busy year by starring in Burberry's lavish Christmas ad. So it comes as no surprise that this stunning gown is a custom creation by the brand, designed especially for Sienna. Posing for photos in the gown, Sienna looked radiant. Take a closer look at all the details now, then stay tuned to see if she tops our best dressed list for the second year running!