Sienna Miller Long Blonde Slightly Wavy

This natural beauty can look fabulous with just about any hairstyle, and this one is a great look for summer.

Sienna Miller and Mario Testino

This style is just parted in the middle and bang-less with slight bends in otherwise straight hair. Allowing the locks to dry naturally after combing out smooth and then a touch of scrunching here and there could get you a similar look.