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)

An alligator is skinned at All American Gator August 16, 2006 in Pembroke Park, Florida. The company processes gators for their skins, meat and trophies and was at full capacity a day after the start of gator hunting season. This year more than 4,000 licenses were sold with each license allowing hunters to kill two gators. The hunt has been expanded by 41 days over previous years, running August 15 to November 1. (Photo by Joe Raedle/Getty Images)

The hot air balloon “Hopper T Frog” from Park City, Utah, peeks over the red rock cliffs during the 23nd Annual Red Rock Balloon Rally at Red Rock State Park December 6, 2003 near Gallup, New Mexico. (Photo By Douglas Tesner/Getty Images)

CANNES, FRANCE - NOVEMBER 03: Italian Prime Minister Silvio Berlusconi leaves the conference centre after the first day of the G20 Summit on November 3, 2011 in Cannes, France. World's top economic leaders are attending the G20 summit in Cannes on November 3rd and 4th, and are expected to debate current issues surrounding the global financial system in the hope of fending off a global recession and finding an answer to the Eurozone crisis. (Photo by Dan Kitwood/Getty Images)

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)

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)

A Maori soldier runs as New Zealand's soldiers march down the Champs Elysees in Paris during a rehearsal of the annual Bastille Day military parade on July 12, 2016. (Photo by Thomas Samson/AFP Photo)