The Shakespeare In Love star has joined forces with Humane Society International/UK in writing an open letter to the Department for Environment, Food and Rural Affairs (DEFRA) Minister Richard Benyon urging him to champion the cause.
Fellow British actors Brian Blessed and Martin Clunes have also signed the I'm There For The Polar Bear petition in a bid to end the killing of polar bears for their parts, which are traded on the global market as rugs, trophies and ornaments.
In the letter, the signatories call on Benyon to support a U.S. proposal to increase protection for the animals.
The plan will be unveiled at the Convention on International Trade in Endangered Species (CITES) in Thailand in March (13).
Fiennes says, ""Polar bears are having a hard enough time surviving the challenges of climate change. Surely we humans can give them a break by ending the commercial hunting of these magnificent creatures. A world without polar bears would be very bleak indeed, so I for one proudly stand with Humane Society International and declare I'm There For The Polar Bear!""
Blessed adds, ""Polar bears are such awesome creatures, we must do everything we can to protect them. They face such an uncertain future with immense threats from oil exploration and climate change, and we are only making their survival harder by allowing them to be killed and sold around the world. The polar bear is in great danger of becoming extinct. We must save them, before they are gone forever.""