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)

Attendees visit the Ford booth during Auto China 2018 show held in Beijing, China, Wednesday, April 25, 2018. Auto China 2018, the industry's biggest sales event this year, is overshadowed by mounting trade tensions between Beijing and U.S. President Donald Trump, who has threatened to hike tariffs on Chinese goods including automobiles in a dispute over technology policy. (Photo by Ng Han Guan/AP Photo)

A Hezbollah supporter fires a rocket-propelled grenade in the air to celebrate the arrival of Iranian fuel tankers to Lebanon, in the eastern town of Baalbek, Lebanon, Thursday, September 16, 2021. The delivery violates US sanctions imposed on Tehran after former President Donald Trump pulled America out of a nuclear deal between Iran and world powers three years ago. (Photo by Bilal Hussein/AP Photo)

Cardboard cut outs of the faces of three candidates for the Republican nomination for the 2016 US Presidential election (L-R) Ted Cruz, Donald Trump and Marco Rubio, are seen set up on urinals in a pub in London on March 1, 2016 as part of an informal poll for customers to log which they dislike the most. Part of the satirical television show The Last Leg, customers at the pub are able to choose which urinal to use and then log their poll on a list on the wall afterwards. (Photo by Justin Tallis/AFP Photo)

Colorado Gov. John Hickenlooper shows off his socks--one with Democratic presidential candidate Bernie Sanders and the other with Republican candidate Donald Trump – before entering his former brewpub for a book signing event to mark the release of his autobiography Thursday, May 26, 2016, in Denver. Hickenlooper, who is term-limited, is doing book talk rounds this week, reviving speculation that he is positioning himself to join Hillary Clinton's presidential campaign ticket. (Photo by David Zalubowski/AP Photo)

A neighborhood watch volunteer stands guard on her street on February 9, 2017 in Peronia, Guatemala. Residents of Peronia, south of Guatemala City organized block by block to secure their community after ten of their neighbors in January were killed, they say, for refusing to pay extortion money to gangs. Armed with machetes and sticks, residents take turns each night, baring strangers' entry into their neighborhoods. Violence and poverty continue to drive emigration from Central America to the United States, even as the Trump administration moves to tighten border security. (Photo by John Moore/Getty Images)

U.S. Secretary of State John Kerry stands inside the historic Shackleton hut near McMurdo Station, Antarctica, Friday, November 11, 2016. Kerry became the highest-ranking American official to visit Antarctica when he landed for a two-day trip on Friday. He's been hearing from scientists about the impact of climate change on the frozen continent. Kerry's aides described the trip as a learning opportunity for the secretary of state. He has been receiving briefings from scientists working to understand the effects of climate change on Antarctica. Kerry has made climate change an intensive focus of American diplomacy during his term, and had previously spent decades working on the issue as a U.S. senator. Trump has called climate change a hoax and said he would “cancel” U.S. involvement in the landmark Paris Agreement on global warming. (Photo by Mark Ralston/Pool Photo via AP Photo)

Palestinians scuffle with Israeli forces at Damascus Gate in Jerusalem's Old City on December 8, 2017. Palestinians clashed with Israeli security forces after calls for a “day of rage” as US President Donald Trump's declaration of Jerusalem as Israel's capital sent shockwaves through the region for a second day. (Photo by Thomas Coex/AFP Photo)