Madonna, Kate Moss, Victoria Beckham and Anne Hathaway were among guests at Monday night's (04.05.09) Costume Institute Gala's 'The Model as Muse: Embodying Fashion' event.

Madonna (50) stunned onlookers at the gala evening — which was held at New York's Metropolitan Museum of Art to launch the institute's spring collection — by donning thigh-high boots and a tiny blue ruffled dress topped with a bizarre headpiece.

Only 'Gossip Girl' star Leighton Meester made a worse choice, shunning a pretty gown for a garish printed jumpsuit.

The event's co-host Kate Moss embraced the Greek theme by donning a daring toga-inspired metallic dress and headpiece.

She was accompanied on the red carpet by the frock's creator Louis Vuitton designer Marc Jacobs, who chaired the evening which is regarded as the biggest night on the fashion calendar.

Victoria Beckham also won praise for her Louis Vuitton outfit, a cute polka-dotted minidress with a long sweeping train which showed off her toned back and legs. Anne Hathaway opted for a short dark purple Marc Jacobs '80s-style gown, while many other stars — including Katy Perry, Blake Lively and Claudia Schiffer — opted for blue.

Jessica Biel showed her devotion to boyfriend Justin Timberlake — who also hosted the glitzy evening — by wearing a flowing Spanish-style red dress from his William Rast clothing line, while Eva Longoria and husband Tony Parker opted for matching black.

Pregnant model Heidi Klum's lavish J Mendel sweeping gown reportedly took over a month to make, while Liz Hurley's peach Estee Lauder frock was a similar full-length, full-skirted style.

Stella McCartney was well-represented, with friends Kate Hudson, Kate Beckinsale and Liv Tyler — who joked she had been "forced" into wearing her gown — choosing her creations.

Other stars at the event included Rihanna, Kanye West, Rachel Weisz, Cindy Crawford, Kirsten Dunst, Bono , Tyra Banks, Mary-Kate and Ashley Olsen, Eva Mendes and Renee Zellweger.