I think Anne-Marie's expression in this photo might be because of one of two things. Either:
a) She knows that the Ruby Olive Wreath Tiara is my favorite Greek tiara, so she's going to get props from Mad Hattery tonight, or
b) She is up to some serious no good!
Unfortunately, one thing she was not up to was lending one of the Greek tiaras to this lovely lady:
I mean, Tatiana's going to be "Princess Nikolaos of Greece and Denmark" in a few months -- couldn't she have had a tiara trial run for the wedding? This dress is spectacular, and it's just screaming for a nice little delicate tiara -- maybe something in gold? That would be unusual!
Anyway: Anne-Marie. The tiara was a home run, the dress was just a base hit. Here's a full-length photo...
Queen Anne-Marie and King Constantine