This was an event celebrating Diane Keaton, so I can see where you might want to wear something a little quirky. (Personally, if I were Emma, I might have Opted For Trousers — if anyone could pull off the Slouchy Diane Keaton Pants and a Hat aesthetic, it’s Emma Stone. Actually possibly also Emma Watson. Also probably Lupita. Michelle Dockery, too, I think. Constance Wu could do it. Probably also…okay, so the list isn’t that short. But Emma Stone is on it!) On the other hand, it might be bad form to show up at an event honoring a person in costume as said person, and this might have enough of a whiff of the preppy menswear-adjacent vibe to be the perfect choice:
I also sort of like how the plaid mid-section of this dress makes her look like she’s been caught in the middle of changing her outfit entirely via magic.