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Goldene Kamera 2013 - Red Carpet Arrivals

BERLIN, GERMANY - FEBRUARY 02: Sigourney Weaver attends the 48th Golden Camera Awards at the Axel Springer Haus on February 2, 2013 in Berlin, Germany. (Photo by Luca Teuchmann/WireImage)

Earth Day: Stars and Their Environmental Causes

We're celebrating Earth Day by taking a look at stars who are taking an active role in protecting our planet with their charitable work.