At the MTV Movie Awards, Leighton Meester eschewed the preppy Upper East Side garb de rigueur for her Gossip Girl character, Blair Waldorf, in favor of a far edgier ensemble: a sultry cut-out dress by Emilio De La Morena with purple suede booties by Brian Atwood. The actress took the stage with Lil Wayne (who joked about plans to guest-star in season three of Gossip Girl) to present the award for best song, which Miley Cyrus won for “The Climb,” featured in Hannah Montana: The Movie.

Burberry devotees gathered at New York’s Palace Hotel last night to celebrate Burberry Day (for which an official decree was issued by Mayor Bloomberg) and witness the illumination of three huge signs on the British luxury brand’s U.S. headquarters. Attendee Blake Lively, luminous herself in a monochromatic gray ensemble by the label of the hour, must’ve felt right at home: Her Gossip Girl character, Serena van der Woodsen, resides in the Palace.

Film-industry heavyweights turned out in droves for the annual Cinema Against AIDS benefit, hosted by the American Foundation for AIDS Research, at the Cannes Film Festival. French actress Marion Cotillard, who won an Academy Award last year for her memorable portrayal of legendary chanteuse Edith Piaf in La Vie en Rose, looked elegant in an embellished mint-green gown by Christian Dior. Cotillard’s upcoming projects include Rob Marshall’s movie musical Nine and Michael Mann’s crime drama Public Enemies, which also stars Christian Bale and Johnny Depp.

American Idol alum (and ELLE cover girl) Carrie Underwood appeared at the second installment of season eight's two-night finale in a ruffled pink frock from Jenny Packham's Pre-Fall 2009 collection, which she complemented with a silver Fizzy clutch by Daniel Swarovski. The Grammy-winning country star closed Tuesday's show, which saw the final face-off between victor Kris Allen and runner-up Adam Lambert, with a fitting cover of the 1985 Mötley Crue ballad "Home Sweet Home."

Opinions may have been divided on Danish director Lars von Trier’s violent new drama, Antichrist, about a couple grieving the loss of their son. But at the controversial film’s Cannes premiere, star Charlotte Gainsbourg looked indisputably stylish, in a black-and-white silk dress by Balenciaga, which she accessorized with gold and silver twisted cuffs, a classic clutch, and strappy sandals (we’d expect nothing less from a member of her notoriously chic family).

Director Alejandro Amenabar’s historical epic Agora, about the brilliant 4th-century astronomer Hypatia, premiered at the Cannes Film Festival Sunday. Lead actress Rachel Weisz made a brilliant fashion choice, wearing an elegant floor-sweeping emerald-green chiffon gown by Valentino to the event. Weisz also stars in Rian Johnson’s forthcoming con-artist comedy, The Brothers Bloom.
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The opening ceremony of the 62nd Cannes Film Festival was attended by plenty of boldface names—Asia Argento, Aishwarya Rai, Robin Wright Penn, and Elizabeth Banks all turned out for the elegant event. Banks, one of the three faces of L’Oreal, looked particularly stunning in a bold one-shoulder gown from Armani Privé’s spring 2009 haute couture collection.