US actor George Clooney arrives with his wife, Lebanese-British lawyer Amal Ramzi Clooney, for the Metropolitan Museum of Art Costume Institute Gala 2015 celebrating the opening of "China: Through the Looking Glass," in Manhattan, New York May 4, 2015. [Photo/Agencies]

One of the world's most watched women, Amal Clooney, arrived on her husband's arm in a tiered ruby-red gown by John Galliano for Maison Margiela.

And another widely watched woman, Lady Gaga, wore a huge kimono-like garment studded with feathers by Balenciaga. Gaga drew cheers when she waved to the crowd packed behind bleachers across Fifth Avenue from the museum.

Actress Kristen Wiig embraced the evening's color scheme, wearing a flowing yellow chiffon number by Prabal Gurung, who accompanied her on the carpet.

Jennifer Lopez bared a lot more skin in a red Versace gown with sheer side panels.

Kim Kardashian opted for sheer, too, in a white gown with a feathery train by Peter Dundas for Roberto Cavalli, the designer's first for the house. Little sister Kendall Jenner went with Calvin Klein, sparkling in green with sexy laces on each side. Mom Kris was there, too, in a bright red draped gown with a gold belt.

Anne Hathaway shimmered in a sleek hooded body-skimmer from Ralph Lauren. Her hair in a temporary bob, Katie Holmes took Zac Posen's arm in one of his designs, a sparkly blue gown with cutouts at the back.