First of all, who even knew they were friends? Actually, I just realized that you don't see Katy Perry and Rihanna hanging out as much as you used to. My theory is that Katy Perry can't deal with Chris Brown, like, at all, and therefore isn't socializing with RiRi now that they're back together. I do not blame her.
I do, however, blame her for this. She has made a giant tactical error in not putting her hair in a beehive here. If you're going retro, go full retro, dude.
Allison Williams looks great. She has gotten very actress-y and polished looking since the premiere of Girls, where the other three women haven't changed THAT much, and I feel like Lena Dunham has kind of been reacting to that a bit this season (like in the scene where Rita Wilson told Marnie she'd lost too much weight in the face, and a couple of other moments). This dress is lovely, though, and she wears it well.

These two seriously fell out of the Grammys 1973.
I don't feel that it's necessary for me to provide any further comment.

They're still there.
This sort of reminds me of that time that Lady Gaga wore icicles all over herself, except not as annoying. And THAT reminds me that a Grammys without Lady Gaga is totally relaxing and kind of nice.
So I guess things are going well for them. This event is, of course, the party that was happening the night Whitney Houston died (it's the night before the Grammys every year) and ergo I now always think of it as the YOU GUYS, WHITNEY HOUSTON IS DEAD Party, which makes the grab-ass feel a little less appropriate.
On the other hand, is kind of great. I loved it on Emily Blunt and I love it now.