Prabal Gurung had every reason to celebrate on Wednesday night. Riding on the major critical success of his recent spring and fall ready-to-wear shows, the designer recently turned out a secondary line for Japanese brand ICB, which launched yesterday with a summertime cocktail party at Barneys Co-Op. With bottomless Corona and Dos Equis, a pop-up popsicle stand by La Newyorkina, and a DJ set by Mia Moretti, it was no staid industry affair.

Rainy weather forced the party from the roof to the sales floor, but that was all the better for the bass to reverberate during Moretti's set, and later during an upbeat performance by one of Prabal's favorite new finds, electro-indie-rock duo Tanlines. The mood in the room may well have been inspired by the designer's festive new collection—with so many guests wearing his particolored prints, the wardrobe certainly was. "I just think the attitude of it is slightly different," Gurung told us. "A little more fun."

As guests browsed the brand-new ICB racks between salsa-verde tacos and cucumber-lime pops, the night felt like both the perfect send-off to summer and an enticing preview for the schedule of Fashion Week parties on the horizon. When we asked whether the ICB project had complicated his preparations for SS13, Prabal laughed, "Things definitely got busier." Luckily, he found time to unwind last night before provisions for September hit full speed.

A crowd of Prabal's nearest and dearest came out in support, including hosts Hannah Bronfman, Elin Kling, and Leandra Medine, as well as Hanne Gaby Odiele, who walked in ICB's digital runway show (which was looped in reverse by the DJ booth to psychedelic effect). More than a brand launch or a photo call, the evening was intended first and foremost to be a good party. "That's the thing about Prabal," Medine explained to us at the end of the night, "I've never been to a fashion party that handed out bourbon. If that's not the number-one indication that we're at the right place, I don't know what is." —Zack Etheart