The countdown is on to the world's biggest fashion party. Fashion's Night Out 2012 is only 15 days away and we can hardly contain ourselves. And just when we thought we couldn't be anymore pumped about the annual fashion extravaganza, FNO releases a super fab PSA video.

R&B crooner Usher opens the video that boasts big names like Marc Jacobs, Justin Bieber, model Liya Kebede and NBA baller Tyson Chandler all grooving to Glee actor Darren Criss aptly singing a cover of Madonna's "Dress You Up" and telling us just how fab September 6 is going to be.

And what's a proper fashion fete announcement without our favorite style star Solange Knowles? The new Madewell campaign model also makes a cameo in the video, rocking a short curly fro and printed shirt.

The gaggle of stars are all dressed in FNO's limited edition t-shirts, which are available for purchase online with proceeds going towards the New York City AIDS Fund.

Check out the video above and visit the official FNO website for a list of all the parties happening around the country and world. And here are just a few events that we plan on hitting up in NYC:

Diane von Furstenberg: Solange is set to DJ the party at DVF's Washington Street store--Woot woot!
M.A.C Cosmetics: Azealia Banks will be performing at the cosmetic store's 506 Broadway location.
Calvin Klein: Dwyane Wade will be at the 654 Madison Avenue store.
Henri Bendel: The store is literally bringing in the circus-- Cirque Du Soleil will be in the building!
Alexis Bittar: Our favorite jewelry line is throwing a karaoke party at its SoHo store. Best part: anyone who sings a song will get a $50 gift card!

Here's a look back at last year's FNO festivities...

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  • Rachel Roy & Amar'e Stoudemire Attend FNO @ Macy's

  • Tiffany Hines Attends FNO @ Nicole Miller

  • Rachel Zoe & Mary J Blige Attend FNO @ Intermix

  • FNO @ Nicole Miller

  • FNO @ Nicole Miller

  • FNO @ Dior

  • Imany Attends FNO @ Ungaro

  • Miss J Attends FNO @ Macy's

  • Mateo Attends FNO @ Macy's

  • Solange Knowles Attends FNO @ Lord & Taylor

  • Miri Ben-Ari Attends FNO @ Macy's

  • Chanel Iman Attends FNO @ Gucci

  • Genevieve Jones Attends FNO @ Ferragamo

  • Nicki Minaj Attends FNO @ Giuseppe Zanotti

  • Andre Brown and Latoya Scott Brown Attend FNO @ Coach

  • Tika Sumpter Attends FNO @ Giuseppe Zanotti

  • Angela Simmons & June Ambrose Attend FNO @ Giuseppe Zanotti

  • Selita Ebanks, Estelle & Corrine Bailey Rae Attend FNO @ DvF

  • DvF & Anna Wintour Attend FNO @ DvF

  • Nicole Ritchie Attends FNO @ Beverly Center

  • Theophilus London Attends FNO @ Tommy Hilfiger

  • Mary Kate & Ashley Olsen Attend FNO @ JcPenney

  • Guests Attend FNO @ Swarovski

  • DJ Toni K & DJ She Rock Attend FNO @ Fendi

  • Natalie Cole Attends FNO @ Valentino

  • Christina Ricci & Lisa Perry Attend FNO @ Lissa Perry Boutique

  • Arlenis Sosa Attends FNO @ Lancome