If there is one thing we are always certain of, it's that H&M knows how to throw one hell of a party. But what happens when the Swedish high-street brand and the creative director of Balmain, Olivier Rousteing come together and plan one? It turns out to be the most epic blowout that was every bit a fashionably glamorous riot.

Held at 23 Wall Street, an abandoned bank building was turned into a futuristic subway station — next stop: #HMBalmaination. The 800 over invited guests were treated to a star-studded affair that saw a total of 33 celebrities including Diane Kruger, Alexa Chung, Ellie Goulding, Zachary Quinto and of course, Gigi Hadid, and Kendall and Kylie Jenner rocking up in Balmain x H&M.

The highly anticipated fashion show opened with Kendall Jenner followed by Rousteing's fashion squad aka the Hadid sisters, Jourdan Dunn, Karlie Kloss, Joan Smalls and Alessandra Ambrosio. Not just your typical runway show, guests were also entertained with a dance battle between dance groups the Jokers, the Twin Twins, the High Rollers and the Kendalls — a live re-enactment of the collection's TV commercial. The full Balmain x H&M collection was presented along with custom-made pieces in different shades (royal blue, red) and embellishments created just for the show.

As for the surprise musical performance that had everyone playing guessing games before the big reveal, it turned out to be a sweet throwback to the '90s with none other than the Backstreet Boys taking stage. Singing Everybody, I Want It That Way and Larger Than Life, Brian, Nick, A.J., Howie and Kevin looked every bit the boy band we remembered them to be decked out in full Balmain x H&M looks. 

With the adrenaline rush from BSB, guests were then invited to shop the collection ahead of the launch at the pop-up. Probably the most expensive H&M collab collection to date, the re-issued hand-embellished and encrusted numbers that cost US$500 and more a pop were the most prized possessions of the night, and understandably so. 

1. First stop: Cocktails before the show

2. The mezzanine runway venue

3. The Balmain x H&M commercial directed by Johan Sandberg & Henrik Timonen

4. Kendall Jenner opens the show

5. Bella Hadid

6. Joan Smalls

7. Gigi Hadid wearing a custom-made look

8. Karlie Kloss

9. Finale walk

10. Olivier Rousteing 

11. Surprise musical appearance by Backstreet Boys

12. Brian, Howie, Nick, Kevin and A.J. decked out in Balmain x H&M

13. Gigi Hadid and Kendall Jenner 

 14. The craze at the pop-up shop

15.  Balmain x H&M Happy Meals served as fashion fuel after shopping
Balmain x H&M New York Happy Meal

Watch the full runway show below: