Diane Kruger joined her close pal, designer Jason Wu, for last night's Green Auction: A Bid to Save the Earth at Christie's in NYC. She went extra casual for a morning Big Apple stroll before changing into one of Jason's designs for the party, which also brought out Zoe Kravitz, Olivia Palermo, Seth Meyers, and Anna Wintour. Nicki Minaj was on hand to entertain everyone following a runway show, and she took the eco theme literally by donning a half-green wig. It was the second-ever bash held to benefit four environmental charities, and was cochaired by Anna, Salma Hayek, and Francois-Henri Pinault. Salma and her husband popped up for last year's event along with Earth Hour spokeswoman Miranda Kerr.