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)

This picture taken on December 17, 2013 shows people taking photos of a pole dancer (R) practising after it snowed in Tianjin during a promotional event by members of China's national pole dancing team and students of the sport. China set up its first national pole dancing team in Tianjin in 2012 in order to compete in the World Pole Dancing Championships. (Photo by AFP Photo)

A villager jumps during “Los Sidros y Las Comedias”, a traditional festival in Spain's northern village of Valdesoto, January 8, 2017. (Photo by Eloy Alonso/Reuters)

Female winner Ane Guro Moen at Hardangervidda Marathon on September 2, 2017 in Eidfjord, Norway. Hardangervidda Marathon goes through parts of the National Park of Hardangervidda, passing through glaciers and waterfalls. (Photo by Kai-Otto Melau/Getty Images)

Hisakata Hiroyuki, a talented photographer from Japan, has managed to snap a group of mortal tomcats in a variety of high-flying kung fu poses. Using his own rapid-fire reactions, he photographs the lovable cats flying through the air, their legs and paws outstretched, like something out of an action movie. (Photo by Hisakata Hiroyuki/Caters News Agency)

People take a selfie with a sawdust and flower carpet during the feast of Corpus Christi in downtown Trujillo, Peru, May 26, 2016. (Photo by Mariana Bazo/Reuters)

Elio Angulo (bottom C) lies inside a cardboard coffin next to Alejandro Blanchard as they introduce their product to potential customers at a mortuary in Valencia, in the state of Carabobo, Venezuela August 25, 2016. When Venezuelan entrepreneurs Alejandro Blanchard and Elio Angulo decided to create cardboard coffins, they were looking for an ecological selling point to compete against classic wood and brass caskets. Three years on, with the oil-rich country mired in deep economic crisis, their “bio-coffins” are becoming a viable option because of high prices for wooden coffins and shortages of brass ones. (Photo by Marco Bello/Reuters)

UK “Ex on the Beach” star Chloe Goodman rocks some serious sideboob in a slinky green outfit on a night out in London, England on September 13, 2016. (Photo by XposurePhotos.com)