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)

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 Herero man holds the head of a freshly butchered cow, killed to supply meat for a funeral, 2012. (Photo by Jim Naughten, courtesy of Klompching Gallery, New York)

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)

Television actress Catherine Fuller visits Trafalgar Square in London and feeds the famous pigeons. (Photo by Harry Kerr/BIPs/Getty Images). 26th June 1956

Presenters Jennifer Lopez and Cameron Diaz speak onstage during the 84th Annual Academy Awards held at the Hollywood & Highland Center on February 26, 2012 in Hollywood, California. (Photo by Kevin Winter/Getty Images)

ne committed photographer spent a grand total of 3,000 dive hours trying to get the perfect shots, capturing beautiful images of a rare shark feeding frenzy. Laurent Ballesta’s images show the glimmering gray reef sharks hunting in swift packs, flying through the water and feasting on the likes of helpless grouper. (Photo by Laurent Ballesta/Caters News Agency)

A tattoo of the model who presents a creation by designer Maxime Simoens is seen in detail, as part of his Haute Couture Spring-Summer 2019 collection show for fashion house Azzaro Couture in Paris, France, January 21, 2019. (Photo by Gonzalo Fuentes/Reuters)