Front Row Star Favorites from Spring 2011 Fashion Week

Taylor Swift and Rachel Bilson

Celebrities filled the front rows during Spring 2011 Fashion Week in New York, London, Milan and Paris. Here, Taylor Swift and Rachel Bilson were pleased with what they saw at the Roberto Cavalli Spring/Summer 2011 show at Milan Fashion Week. After the show, both ladies packed up to head to Paris, where they helped Cavalli celebrate the 40th anniversary of his eponymous label at a chic gala.

Kim and Kourtney Kardashian

Kim Kardashian

and sister Kourtney took in the Jill Stuart Spring 2011 show.

Kelly Osbourne and Kanye West

After making a surprise appearance at the Jay-Z concert at Yankee Stadium earlier that week, Kayne West hit the Jeremy Scott fashion show alongside Kelly Osbourne.

Sarah Jessica Parker and Rachel Bilson

Fellow fashionistas Sarah Jessica Parker and Rachel Bilson attended the Diane von Furstenberg Spring 2011 show in dresses by the designer.

Rihanna

Rihanna

was the center of attention at the the Miu Miu show, accessorizing her graphic-print dress with her color-coordinated nails, lips and hair.

Leighton Meester

Gossip Girl Leighton Meester (in Marc Jacobs) hit the V Magazine bash at New York's Standard Hotel.

Jessica Simpson

Singer Jessica Simpson was all smiles at the Project Runway show at New York's Lincoln Center. The star (and designer) was also the guest judge on the season finale.

Katrina Bowden, Christian Siriano and Maggie Grace

30 Rock

's Katrina Bowden and Lost's Maggie Grace gathered around designer Christian Siriano backstage at his runway show. The designer also debuted his collection for Payless on all of the models.

Karl Lagerfeld and Blake Lively

Chanel

re-opened its Soho boutique in New York City last night, where designer Karl Lagerfeld stayed close to Gossip Girl star Blake Lively, who donned a glimmering Chanel dress from the Fall 2010 collection for the occasion.

Claire Danes and Shenae Grimes

Claire Danes sat with 90210 star Shenae Grimes at the Z Spoke by Zac Posen show.

Julianne Moore, Kerry Washington, Isabel Lucas and Katie Holmes

Kerry Washington

(second from left) and Isabel Lucas (second from right) joined Moore and Holmes in the front row at Calvin Klein.

Gwen Stefani and Gavin Rossdale

Following her "African butterfly pattern"-inspired L.A.M.B. runway show, GwenStefani

Jason Wu and Diane Kruger

Jason Wu

posed backstage with friend Diane Kruger (in Jason Wu) at his Spring 2011 runway show.

Sienna Miller

After debuting the Twenty8Twelve Spring 2011 collection earlier in the day, Sienna Miller sat back to watch the Matthew Williamson show at the Battersea Power Station in London.

Diane Von Furstenberg, Marc Jacobs, and Rachel Zoe

Marc Jacobs

posed with fellow designer Diane von Furstenberg and stylist Rachel Zoe after showing his '70s-inspired collection.

Zac Posen and Rashida Jones

Following his Z Spoke show, Zac Posen hung out with with Parks and Recreation star Rashida Jones at the Lincoln Center tents.

Jessica Szohr and Olivia Palermo

Jessica Szohr

and Olivia Palermo wore dramatic Marchesa dresses for the label's Spring presentation.

Alexa Chung

Fashion Week regular Alexa Chung attended the Mulberry Spring 2011 show, donning the label's polka-dot dress and Lily purse. Chung later visited the show's after-party at the Soho House, where she told us she was glad to have finished presenting her Madewell collection: "It's good to be able to let loose a bit and party now."