Model is wearing a size XS
You can wear it with a button up under it, you can wear a sweater, cardigan or blazer over it, or you can wear it by itself
This is a very common and flattering style
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This one referenced an outfit of the same style and color Diana sported during the state visit of West German president Richard von Weizsacker in London in 1986
I almost always choose an airy dress with shorts underneath for a field trip, but if were headed to a farm, I switch to denim shorts instead, paired with a button-down or a striped tee, like outfit #1