Great look for Anne-Marie.
I don't think you will get a credible answer to that question any time soon. All I would say is that blue is not unusual colour for the mother of the bride to wear.Did she wear blue and white because of Greece? That would seemingly make it extra nice.
Queen Anne Marie looked wonderful and the colours of the dress and the pearl necklace all worked so nicely.A wonderful look for Anne-Marie at the wedding today: