In 1988, Sigourney Weaver was nominated for an Academy Award for her portrayal of naturalist and activist Dian Fossey in the film Gorillas in the Mist. Now, nearly 30 years later, Weaver is once again stepping back into Fossey’s boots, this time for National Geographic’s three-part documentary series, Dian Fossey: Secrets in the Mist. Weaver reads Fossey’s letters and writing aloud, providing the narration to the in-depth exploration of the enigmatic woman with no formal scientific training who introduced the world to families of Rwandan gorillas and advocated for their safety until her brutal, unsolved murder in 1985.

“Her letters that I got to read were emblematic of her — her humor and her take on life, and certainly also her love of the gorillas and her frustration and fear for them,” Weaver told EW. “It was wonderful to get to spend time with her again because when I made [Gorillas in the Mist] I didn’t get to meet her. She was such good company.”

The documentary series explores Fossey’s work as a researcher, but also her more radical efforts to protect gorillas against poaching that made her a number of enemies in Rwanda.

“I think she felt that at that point that there was very little understanding of what she was trying to do, and there was huge pressure on the part of the gorilla population from poaching, from laying snares in the forest, from the huge population density,” Weaver said.” I think it’s taken us this long for us to understand and be proactive protectors, and I credit the Rwandan government and President Kagame.”

In addition to representing Fossey on screen, Weaver works as the honorary chairwoman of The Dian Fossey Gorilla Fund, which protects critically endangered gorillas in the Congo and around Fossey’s original research site, Karisoke, in Rwanda. “We have young people from all over Africa coming to study at Karisoke, studying how you conserve and how you get the work you need to do to track all the various stories that we’re telling about breeding and interactions.”

Emerald City - Season 1
Credit: Robert I.M. Campbell; Steve Schofield/National Geographic

Fossey’s legacy lives on in that way, and the NatGeo series also brings her to life by looking at archival footage, diaries, and interviews with her former colleagues.

“To watch the amazing footage that NatGeo has put together from all of their achieves, and to hear her voice through the letters, and to re-experience what it’s like to be with these gorilla families and these gorilla characters, I feel like it’s such a gift that NatGeo is giving to all of us to revisit this,” Weaver said. “And it’s a much more timely experience than how her work ended, because we really don’t know anything about what happened, and we’ll never know, but the good thing is her work continues. The movie she wanted made was made, and I think her story is such an inspiration to the rest of us, and a reminder that these amazing animals are fellow citizens of our world.”

“That’s how Dian saw our world: not that we’re the main species and everything else is subordinate to us, but that we share the planet and that they have a right to life, and that their way of life must be protected as well.”

Dian Fossey: Secrets in the Mist premieres Wednesday at 9 p.m. ET on National Geographic.