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)

Vladislav Doronin and Naomi Campbell attend the religious ceremony of the Royal Wedding of Prince Albert II of Monaco to Princess Charlene of Monaco in the main courtyard at the Prince's Palace on July 2, 2011 in Monaco. The Roman-Catholic ceremony follows the civil wedding which was held in the Throne Room of the Prince's Palace of Monaco on July 1. With her marriage to the head of state of the Principality of Monaco, Charlene Wittstock has become Princess consort of Monaco and gains the title, Princess Charlene of Monaco. Celebrations including concerts and firework displays are being held across several days, attended by a guest list of global celebrities and heads of state. (Photo by Sean Gallup/Getty Images)

English television personality and model Sam Faiers seen attending The Box BRIT Awards 2020 afterparty on February 18, 2020 in London, England. (Photo by Splash News and Pictures)

American model Bella Hadid comes out of her hotel on September 25, 2018 in Paris, France. (Photo by Pierre Suu/Getty Images)

Milan Fashion Week Women SS 2020 – ETRO Spring/Summer 2020 show in Milan, Italy on September 20, 2019. Top model Irina Shayk and other models leaving Etro Fashion Show. (Photo by Pierre Teyssot/Splash News and Pictures)

American model Emily Ratajkowski shows off her new swimwear line in the second decade of March 2022. (Photo by emrata/Instagram)

English singer Rita Ora, 29, made sure all eyes were on her as she headed for a night out in a plunging dress in London, England on September 7, 2020. The sеxy checked dress was complemented with heavy gold jewellery around Rita's wrists and neck. Rita's blonde hair had a sheen as it fell over her shoulders, and she completed her look with glam makeup. (Photo by Instagram/The Sun)

Bollywood actress Chitrashi Rawat lies in a plastic drum as she is briefed by a crew member during the shoot for the film “Black Home” at a beach on the outskirts of Mumbai April 26, 2013. (Photo by Danish Siddiqui/Reuters)