Why Jessica Chastain and Justin Theroux geek out over Alexander Wang

Distance, it seems, does make the fashion heart grow fonder. At least, judging by the turnout to see Alexander Wang launch his H&M collection at the Armory on the Hudson in Washington Heights. We're talking Mary J. Blige, Dakota Fanning, Kate Mara and Justin Theroux.

The amazingly classy and sweet Jessica Chastain was there. "We are we?" she joked.

And unlike other celebs, who go to high-profile fashion shows but then refuse to, you know, do press while there, she was chatty and friendly. She'd worked with Wang pre-show to find the perfect ensemble.

"How cool is he, right? I'm wearing reflectors. We talked about what I liked. I'd met him before. We talked through email. I looked at a bunch of dresses. As soon as I put this on, I loved it," she said.

Yeah, so did we. The collection was pretty killer.

It includes cropped bra tops, oversized sweatshirts, roomy jackets, boxing gloves, parkas -- and socks.

The collection launches in stores on Nov. 6, but we got a sneak preview -- and got to shop. Yes, lucky us. And we talked to Wang pre-show.

"They approached us. We knew that there had to be newness. We came up with the idea to do a sportswear collection. It wasn't a regurgitation of things we'd done previously," said the designer, of the genesis of the collection, which is ultra-cool sportswear. "I just like to be comfortable. I've always been very inspired by people who don't have dress codes and dress for themselves. I'm not an athlete. I don't go to the gym five days a week."

He's also the creative director of Balenciaga, plus mans his two collections, Alexander Wang and T by Alexander Wang. Does he ever sleep? "Yes, on planes," he laughed.

And after shows in Brooklyn and a pier along the Hudson River, how did he find this latest location, way, way, way uptown?

"A lot of research. Fashion shows and events can get very stale. We like to bring the audience somewhere new," he said.

Justin Theroux also turned up, sans fiance Jennifer Aniston. He's a longtime fan of Wang as well.

"I like his colors -- or lack of colors. I like black and white. He's always been really good to me. It's a lot of good winter gear as well. I'm wearing some pants of his," he said.