Well, this is the creepiest look Mary has worn.
Her hair worn in long waves with highlights is clearly Kate's current hairstyle.
Then she wears the.same.dress as Kate! Mary has a huge closet full of clothes Kate hasn't worn, and Mary has never been shy of buying new clothes. She could've easily chosen a dress Kate hasn't worn, but she chose this one.
Celebrities usually try to wear unique outfits to define their own brand. Sometimes celebs might wear the same outfit, but usually they style them differently - and certainly they don't copy each other's hairstyles too.
She watches Kate probably obsessively.
If I saw an acquaintance or even a fan imitate my exact look (and not in jest), I would freak out.
I'm thinking horror movie!