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)

A mock-up of a typical British suburban home is seen sinking into the River Thames, in a protest by Extinction Rebellion to demand faster government action on climate change in London, Britain on November 10, 2019. (Photo by Extinction Rebellion/Handout via Reuters)

“The series of photos called Workwears, by French photographer Bruno Fert, visually juxtaposes people’s private lives with their lives at work. A firefighter, a fisherman, a nurse, a diver, a judge. One by one, Fert’s photos show people in their homes wearing everyday clothing – followed by another photo showing them dressed in the clothing of their chosen professions. Our reaction, Fert said, reminds us how tightly humans hold on to certain stereotypes about some professions. “I like to break those stereotypes”, he said”. – Thom Patterson via CNN. Here: Lola is seen at left in everyday clothes – and then at right in her work clothes. She works as a clown in Paris. (Photo by Bruno Fert/Picturetank)

Guillaume Rolland of France stands on the line during the Highline Extreme event in Moleson, Switzerland September 25, 2015. European best slackliners will compete until Sunday on six different lines ranging from 45 metres (148 ft) to 495 metres (1,624 ft). The 495 metres (1,624 ft) line if completed, will be the world record. (Photo by Denis Balibouse/Reuters)

TV host/blogger Louise Roe attends The Weinstein Company's Academy Awards viewing and after party in partnership with Grey Goose at TAO Los Angeles at TAO Hollywood on February 26, 2017 in Los Angeles, California. (Photo by Rachel Murray/Getty Images for The Weinstein Company)