This Party Was Like a Who's Who of Hollywood's Best Dressed

The actress showed off her bump in a fitted Gucci minidress with a leather jacket, which she finished with Brian Atwood heels and a pair of Jennifer Meyer earrings.

Molly slipped into a red-and-nude slip dress with a flirty '20s vibe.

The 12 Years a Slave breakout star showed her fashion chops in a cutout and crisscrossed black Proenza Schouler cocktail dress, which she accented with a chic white clutch in hand.

Kirsten posed alongside Garrett Hedlund in a graphic Rodarte midi dress and ankle boots.

The Modern Family knockout opted for a lacy, long-sleeved mini to show off her stems.

Downton Abbey's star brought the color in a bright Altuzarra sheath and yellow Christian Louboutins.

Marisa Tomei took the casual-cool approach in a bright blouse and leather trousers.

Amy Adams ditched her American Hustle vibe in favor of a sophisticated blazer-style dress and nude pumps.

The model stepped out in a chic black jumpsuit with a gold necklace and coordinating Louboutins to finish it all off.

Cate Blanchett topped an easy black jumpsuit with a statement necklace and completed the look with black booties.

Ever the fashion darling, Allison opted for a sleek, belted black v-neck sheath dress from Calvin Klein Collection and understated heels.

The style-savvy star accented her striped black-and-white dress with a bold red lip and a pair of metallic Louboutins.

Dita Von Teese went for the drama in a gold-tinged floral gown and tassel-drop earrings.

Sarah Hyland finished her bold orange look with an exotic, multicolored clutch and strappy sandals.

Naomie wowed in a white, textural Marni mini and a pair of black sandals, which she accessorized with a Delfina Delettrez ring.