Dudley O’Shaunessy, Olivier Rousteing, Kendall Jenner and Gigi Hadid 

The launch of the highly-anticipated Balmain x H&M collaboration kicked off last night. In true Olivier Rousteing style, the collection launched with a star and model-studded runway event in New York—with Kendall Jenner, Gigi Hadid, Jourdan Dunn, Karlie Kloss and more hitting the runway. And how else does Rousteing ring in one of the biggest fashion collabs of the year? By closing off the runway show with a surprise Backstreet Boys reunion performance, of course. See the best Instagrams from the show, surprise performance and after party below, plus see the full Balmain x H&M lookbook here.  The collection will be available at H&M Lot 10 and H&M Avenue K on November 5, 8am.

Kylie Jenner watches on as Kendall opens the show.

@kendalljenner opening the #HMBALMAINATION show. Proud lil sis @kyliejenner watching front row. @balmainparis @hm

A photo posted by Coco Rocha (@cocorocha) on Oct 20, 2015 at 5:38pm PDT

The Backstreet Boys put on a surprise performance. 

Watching @backstreetboys perform at the @balmainparis @hm #HMBALMAINATION event like its 1998 all over again.

A video posted by Coco Rocha (@cocorocha) on Oct 20, 2015 at 6:57pm PDT

Karlie Kloss walks the show, too.

@karliekloss walks in @hm x @balmainparis #hmbalmaination | #TeamBFA photo by @alexanderstein for BFA.com #BFApartnerships

A photo posted by Images Matter. (@bfa) on Oct 20, 2015 at 5:43pm PDT

Olivier Rousteing poses with Kendall Jenner, Gigi Hadid and Dudley O’Shaunessy

THE #HMBALMAINATION SQUAD #KendallJenner #OlivierRousteing #GigiHadid and #DudleyOshaughnessy backstage at the Balmain x @hm launch event in NYC

A photo posted by BALMAIN (@balmainparis) on Oct 20, 2015 at 6:41pm PDT

Coco Rocha on the way to the show.

SPOTTED! Ezurin Khyra, Hofit Golan and Victoria Bonya at the launch of Balmain X H&M

Image: Getty

Via: HarpersBAZAAR.com