Answer after the jump
If you guessed Dior to the Princess Grace Awards in 2011. You’re absolutely right. Here’s a photo of Prince Albert and Princess Charlene with Julie Andrews. I wrote about it 7 years ago HERE (before I learned how important punctuation is).
These are the Montblanc earring the Princess wore that night. They’re called the Seven Stars. The princess wore them another time that same year, remember when?