Rarely does the 28-year-old ever try to hard or over do it, and she always looks effortlessly glamorous.
Of course, it always helps if you are as naturally stunning as Rosie is, but we can start by emulating her fashion sense.
With the weather so turbulent, what we need are breathable, flowing fabrics, that work just as well in the heat as they do with a little chill in the breeze.
And Rosie showed us exactly how to do it with this beautiful summer evening outfit.
With a cross front white blouse tucked into floral trousers, Rosie looked comfortable yet chic.