Rihanna attends the Balmain show as part of the Paris Fashion Week Womenswear Fall/Winter 2014-2015 on February 27, 2014 in Paris, France. (Photo by Dennis Leupold/The Guardian)

French actress Audrey Tautou arriving to the Balmain show as part of Paris Fashion Week Fall/Winter 2020/2021 on February 28, 2020 in Paris, France. (Photo by Meryl Curtat/SIPA Press)

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)

Rusting old petrol pumps outside a long-closed rural village petrol station are seen on a minor road near Trowbridge, Britain, October 21, 2016. From art deco apartments in Sussex to a trendy burger bar in London, some of England's former petrol stations are enjoying a new lease of life following creative makeovers. The overhaul opportunities have been created as more than 20,000 stations closed in the United Kingdom over the past 40 years, according to the U.K.'s Petroleum Industry Association (PIC). (Photo by Toby Melville/Reuters)

Sara Sampaio is seen wearing a pink knit sweater and a pink leather skirt during Paris Fashion Week Spring/Summer 2019 on September 24, 2018 in Paris, France. (Photo by Timur Emek/Getty Images)

Father Bruno Lefevre Pontalis stands on the rooftop of Saint Francois Xavier church to bless the city of Paris during the national lockdown for Covid-19 at Easter, in Paris, France on April 12, 2020. (Photo by Nathan Laine/Bloomberg)

Models pose backstage prior to the Viktor & Rolf Haute Couture Spring Summer 2023 show as part of Paris Fashion Week on January 25, 2023 in Paris, France. (Photo by Vittorio Zunino Celotto/Getty Images)

A woman looks at an artwork during the preview of the Art Paris 2020 held at the Grand Palais in Paris, France, September 9, 2020. Originally scheduled for April, Art Paris, France's second-biggest modern and contemporary art fair, opens its door to the public from Sept. 10 to 13. (Photo by Chine Nouvelle/SIPA Press/Rex Features/Shutterstock)