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)

The Thom Browne Fall 2015 collection is modeled during New York Fashion Week, Monday, February 16, 2015. (Photo by Diane Bondareff/AP Photo)

A Citroen Ami One concept car sits on display during the media day of the Auto Shanghai 2019 motor show in Shanghai, China, 16 April 2019. The 18th Shanghai international automobile industry exhibition runs from 16 to 25 April. (Photo by Wu Hong/EPA/EFE)

Hundreds of pumpkins lie on a field near Frankfurt, Germany, after sunset on Wednesday, October 16, 2019. The autumn vegetable heralds the approach of halloween. (Photo by Michael Probst/AP Photo)

In this photo released by Xinhua News Agency, a worker drinks at the construction site of the T3B terminal project of Chongqing Jiangbei International Airport in southwest China's Chongqing, July 11, 2022. Flooding and extreme high temperatures have caused multiple deaths in eastern China as summer heat descends earlier than usual. (Photo by Huang Wei/Xinhua via AP Photo)

British Holidaymakers seen partying partying in Punta Bella main Street in Magaluf, a major holiday resort on the Spanish island of Majorca this summer, July 2017. (Photo by Splash News and Pictures)

American actress and model Christina Hendricks attends NBC's New York Mid Season Press Junket at Four Seasons Hotel New York on January 24, 2019 in New York City. (Photo by Jamie McCarthy/Getty Images)

English journalist and newsreader Lucy Watson attends the “Charlie's Angels” UK Premiere at The Curzon Mayfair on November 20, 2019 in London, England. (Photo by Jeff Spicer/Getty Images)