Leonardo Dicaprio braced himself for the big freeze while shooting the cover art for Vanity Fair's upcoming Green issue - he posed on a glacier in Iceland. The TITANIC star poses with a baby polar bear, called CANUTE, who was digitally added to the photo. Photographer Annie Liebovitz snapped the baby bear at his Berlin Zoo home in Germany. Robert Redford and former Seinfeld star Julia Louis-Dreyfus are also celebrated as celebrity environmental warriors in the special issue.