The Costume Institute's American Woman Gala

Jessica Alba, in Sophie Theallet for Gap, with House of Lavande jewels and a Ferragamo clutch

Marchesa's Keren Craig and Georgina Chapman, in their own designs, with Eva Longoria Parker, in Marchesa with Harry Winston jewels

Nicole Richie, in Marc Jacobs with Harry Winston jewels and a Marc Jacobs clutch

Vera Wang, in her own design, with Mila Kunis, in a dress by the designer, with Fred Leighton jewels

Michael Kors with Brooke Shields, in a dress by the designer, with Fred Leighton jewels

Rachel Bilson, in Louis Vuitton, with Louis Vuitton jewels, bag, and shoes

Sienna Miller, in Emilio Pucci, with Solange Azagury-Partridge jewels and Emilio Pucci shoes, with Jude Law

Sasha Pivovarova, Sean Lennon, and Kemp Muhl, all in Marni

Gisele Bündchen, in Alexander Wang, with Tom Brady, in Tom Ford

Eva Mendes, in Dolce & Gabbana with Verdura jewels and a Leiber clutch

Demi Moore, in Lanvin with Casadei shoes

Jessica Biel, in Ralph Lauren with Fred Leighton jewels, and Justin Timberlake, in his own design for William Rast with Louis Vuitton shoes and Cartier watch and cuff links

Sarah Jessica Parker, in Halston Heritage, with Fred Leighton and VBH jewels

Gwen Stefani, in L.A.M.B., with Lorraine Schwartz jewels and a VBH clutch, with Gavin Rossdale

Elisa Sednaoui, in Chanel Haute Couture and Chanel jewels, with Karl Lagerfeld

Donatella Versace, in her own design

Chanel Iman, in Michael Kors, with David Yurman jewels and Michael Kors shoes

Cassie, in Versace, with Lorraine Schwartz jewels and Sergio Rossi shoes

Lily Donaldson, in Marc Jacobs, with a Marc Jacobs clutch

Jennifer Lopez, in Zuhair Murad, with Cartier and Stephen Russell jewels and a Leiber clutch

Naomi Campbell, in Dolce & Gabbana

Coco Rocha, in Zac Posen, with Everlon jewels

Blake Lively, in Marchesa, with Lorraine Schwartz jewels

Zac Posen with Doutzen Kroes, in his design with Tiffany & Co. jewels

Kristen Stewart, in Chanel Haute Couture, with Sergio Rossi shoes

Alessandra Ambrosio, in Versace, with Martin Katz jewels

Jessica Stam, in Rachel Roy with Bulgari jewels