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)

Base jumper Denis Odintsov from Russian leaps from the 300-meters Open Deck of the Malaysia's landmark Kuala Lumpur Tower during the International Tower Jump in Kuala Lumpur on September 27, 2013. Some 103 professional base jumpers from 20 countries are taking part in the annual event. (Photo by Mohd Rasfan/AFP Photo)

Guests arrive for the opening ceremony of the 23rd Life Ball in Vienna May 16, 2015. Life Ball is Europe's largest annual AIDS charity event and takes place in Vienna's city hall. The Life Ball is a charity gala to raise money for people living with HIV and AIDS. (Photo by Leonhard Foeger/Reuters)

A girl looks with comic disgust at a guy who falls asleep with a bottle of beer at a party; her friend laughs. (Photo by Edward Corbett/Rex Features/Shutterstock)

The world's biggest wild animal farmer, Carr Hartley of Rumuruti in Kenya, sells animals to zoos, circuses and film companies. (Photo by Maxim Ruston/BIPs/Getty Images). November 1956

A male red deer with antlers covered in bracken, walks through undergrowth in Richmond Park in south west London, October 3, 2014. Over 600 red and fallow deer roam in the largest of London's Royal Parks, and have their numbers managed in an annual cull each November and February. (Photo by Toby Melville/Reuters)

A Rohingya Muslim girl, Saira Begum carries food items distributed in aid as she walks towards her shelter in Taiy Khali refugee camp, Bangladesh, Tuesday, September 19, 2017. With a mass exodus of Rohingya Muslims sparking accusations of ethnic cleansing from the United Nations and others, Myanmar leader Aung San Suu Kyi on Tuesday said her country does not fear international scrutiny and invited diplomats to see some areas for themselves. (Photo by Dar Yasin/AP Photo)

Valentyna Konstantynovska, 79 years-old, holds a weapon during basic combat training for civilians, organized by the Special Forces Unit Azov, of Ukraine's National Guard, in Mariupol, Donetsk region, eastern Ukraine, Sunday, February 13, 2022. The United States is evacuating almost all of the staff from its embassy in Kyiv as Western intelligence officials warn that a Russian invasion of Ukraine is increasingly imminent. (Photo by Vadim Ghirda/AP Photo)