Lord knows we spend enough time covering Gossip Girl around here. So we were obviously thrilled to find ourselves in a real-life Gossip Girl moment last night at the Met before the opening of La Fille du Regiment in which Emmy Rossum schooled Blair — er, Leighton Meester — on the Costume Institute gala. We couldn't believe our ears at what unfolded. How Meester knows so little about the Best Party Ever is a tragic mystery. But perhaps not as tragic as the fact that she won't be going, while Rossum will sit at Anna Wintour's table in a dress handpicked by Her Vogue-ness. Here's what unfolded:

New York: [to Rossum] So who are you wearing to the Costume Institute gala on May 5?
Rossum: Oh, I can't say. But I can say that Anna [Wintour]'s picking it.
Meester: Why is she picking it?
Rossum: Because Anna invited me to sit with her. I'm pretty lucky, aren't I?
Meester: That's pretty great!
New York: Did Anna say to you, "I will pick your dress"?

Rossum: No, I am lucky enough that Anna has kindly said that she'll work with me to get me a great dress. I've been christened. I feel like I was just blessed by the Pope.
Meester: Is it, like, ridiculous — the Costume? They were asking me about it, actually…
Rossum: It's, like, literally amazing. You can't not go. It's like the event of the year.
Meester: I know, but I think I'm going to be in L.A.
Rossum: It's like the New York Oscars…
Meester: May 5, you said? I don't think I'm going to make it.
New York: [to Rossum] Why don't you take her over to Anna and introduce her?
Rossum: She's working. She's not even available to go to the most fabulous event.
New York: [to Meester] You're not done shooting Gossip Girl?
Meester: We'll be done. I'm shooting a different show.
New York: Oh, really — what?
Meester: Entourage. So I won't even be in town — but in L.A.
New York: Are you going to be a recurring part?
Meester: No. I'm just doing this one episode for now. We'll see what happens.
New York: That's pretty cool.
Meester: Yeah, it's pretty good.
Rossum: She has a pretty cool show for now, though.

But one hit show is never enough. —Tim Murphy