The photo project was done for the organization Fishlove and included some other U.K.-based celebrities posing in the buff with critters ranging from bass fish to sharks. Its goal is to raise awareness of how overfishing is destroying the oceans. The release of Gillian's nearly nude pic, which was snapped by French portrait photographer Denis Rouvre, is timed with a European Parliament vote on banning destructive forms of deep-sea fishing in the Northeast Atlantic. The Fishlove organization is trying to rally voters to sign a petition ending deep-sea trawling – which, according to scientists, is negatively impacting the fish population and their habits – and Gillian solicited signatures in a Twitter post. Photo: “Fish Love” Project by Photographer Denis Rouvre. Gillian Anderson. (Photo by Denis Rouvre)

Cheering The News of Germany's Surrender New Yorkers Gather around a youth wearing a mask of Adolf Hitler to cheer the news of the Surrender of Germany on May 7. The Crowd is gathered in times Square, New York. May 08, 1945. (Photo by New York Post/Photo Archives, LLC via Getty Images)

People attend in costume the 2022 New York Comic Con, at the Jacob Javits Convention Center in Manhattan in New York City, New York, U.S., October 6, 2022. (Photo by Brendan McDermid/Reuters)

Model Adriana Lima attends the 19th Annual amfAR New York Gala at Cipriani Wall Street on February 8, 2017 in New York City. (Photo by Splash News and Pictures)

People attend in costume the 2022 New York Comic Con, at the Jacob Javits Convention Center in Manhattan in New York City, New York, U.S., October 6, 2022. (Photo by Brendan McDermid/Reuters)

A woman looks at The Empire State Building and the New York Skyline during a preview of SUMMIT One Vanderbilt observation deck, which is spread across the top four floors of the new One Vanderbilt tower in Midtown Manhattan, in New York City, New York, U.S., October 18, 2021. (Photo by Eduardo Munoz/Reuters)

Romanian riot police detain a man, face covered in blood, after minor clashes erupted during a protest in Bucharest, Romania, Thursday, February 2, 2017. Brief clashes broke out between protesters and police in Romania¹s capital, as tens of thousands of people protested for the second night a government decision to decriminalise official misconduct. (Photo by Vadim Ghirda/AP Photo)

Paris Jackson arrives at the Calvin Klein Collection fashion show during New York Fashion Week at New York Stock Exchange on February 13, 2018. (Photo by Ouzounova/Splash News and Pictures)