Sienna Miller had us all happy that summer is sticking around for another month after she wore this light and breezy floral dress by Dolce & Gabbana to launch the new BMW i3 in London on Monday. The look was so perfect that even I considered buying a BMW, even though I am clearly a gay man who clearly cannot afford to buy a BMW (or, let’s be honest, anything).

Anyway, it was hard for Hollywood to top such a wonderful dress – but everyone certainly tried. Check out great looks from Heidi Klum, Amanda Seyfried and more in this week’s best-dressed roundup.