NY Fashion Week Kickoff Parties

Charlize Theron and Vera Wang

Oscar winner Charlize Theron (here with designer Vera Wang) played host at the unveiling of the new designer floor at Saks Fifth Avenue in New York City. The 50,000 square-foot space is the home of 23 designer shops, including Oscar de la Renta, Carolina Herrera and Vera Wang of course.

Zac Posen and Rachel Zoe

Designer Zac Posen and celebrity stylist Rachel Zoe struck matching poses at the fashionable Saks Fifth Avenue event. Posen, Marc Jacobs and other top designers created exclusive one-of-a-kind cocktail dresses specifically for the launch of the new third floor.

Gwen Stefani

Straight from touring with No Doubt, Gwen Stefani trades in her rocker hat for her designer hat while getting ready to present L.A.M.B.'s Spring 2010 collection at New York Fashion Week.

Blake Lively and Anna Sui

Gossip Girl

star Blake Lively feted designer Anna Sui at the launch party for her Anna Sui for Target line in New York City. The collection-which hits Target stores and target.com on September 13th-was inspired by the preppy-chic characters on the hit TV show.

Michelle Trachtenberg, Penn Badgley and Jessica Szohr

Other sexy Gossip Girl stars to hit the Anna Sui for Target Pop-Up shop-and did a little shopping themselves-included Michelle Trachtenberg (in Rebecca Taylor), Penn Badgley and Jessica Szohr. Word is that Trachtenberg picked up a striped cardigan and Szohr was keen on a zip-front vest.

Molly Sims and Michelle Monaghan

Michelle Monaghan

(in a J. Mendel dress and Boudin necklace) joined hosts Nate Berkus and Stefani Greenfield (not shown) at the launch celebration of Molly Sims's new Grayce by Molly Sims jewelry collection for HSN at Raoul's in N.Y.C. The retro-inspired selection will be available on HSN and hsn.com in November.

Dries van Noten and Maggie Gyllenhaal

Belgian designer Dries van Noten and fashion-loving actress Maggie Gyllenhaal attended the Fashion Institute of Technology's 4th Annual Artistry of Fashion Award Luncheon at Cipriani 42nd Street where van Noten was honored with the Couture Council Award for Artistry of Fashion.

Mischa Barton and Taylor Momsen

The Beautiful Life

's Mischa Barton and Gossip Girl's Taylor Momsen shimmered in metallics at The Cooper Square Hotel Penthouse in N.Y.C. The small screen beauties feted designer Kris Van Assche at a cocktail party hosted by GQ and Dior Homme.

Hayden Christensen and Rachel Bilson

Also enjoying the New York City skyline, including the Empire State Building, from The Cooper Square Hotel were engaged stars Hayden Christensen and Rachel Bilson. Other hot young stars who came out to celebrate the designer included Chace Crawford, Sara Paxton and Josh Hartnett.

Lazaro Hernandez, Leighton Meester and Jack McCollough

Leighton Meester

joined Proenza Schouler designers Jack McCollough and Lazaro Hernandez at the Sundance Channel's premiere of The Day Before in N.Y.C. The four-part documentary follows the pair, along with designers like Karl Lagerfeld, in the final 36 hours leading up to their Fall 2009 season catwalk shows.

The Day Before premieres tonight at 10PM EST on the Sundance Channel.

Michelle Monaghan

Looking fashion-week ready, actress Michelle Monaghan stepped out in a vibrant mini-dress at the opening of the Fenton/Fallon jewelry and accessories boutique in New York City's Lower East Side neighborhood.