Gillian Anderson has taken on a number of roles in recent years, playing real-life, prominent women: First Lady Eleanor Roosevelt, former British Prime Minister Margaret Thatcher, Princess Johanna Elisabeth of Germany, and BBC journalist Emily Maitlis, to name a few. Her latest project, “The Salt Path,” based on Raynor Winn’s autobiographical book of the same name, is another true story of a strong, resilient woman facing a life-changing challenge. But in this film, Anderson trades in her period costumes for a pair of hiking boots.

Screening at the Toronto International Film Festival, “The Salt Path” is the profound story of husband and wife Ray (Anderson) and Moth Winn (Jason Isaacs) who embark on a 630-mile hike along a beautiful but rugged coastline in southwest England after being forced to abandon their family farm. To make matters worse, earlier that same week Moth was diagnosed with a degenerative condition that would lead to difficulty walking and balancing, dementia, the inability to swallow, and eventually death. With all the supplies they need to survive on their backs, they set out on their journey, their bond strengthening along the way; a true story of “it’s the journey, not the destination.”

"When I read the book, I couldn't get it out of my system for weeks," Anderson tells Variety. "It changed my perspective on homelessness, on people living on the streets, on the fact that any of us can become homeless and destitute at any time, and [I] really embraced the depth of my own compassion because it feels like a universal problem that needs to be solved in terms of what happens to individuals who go through that."

As she filmed, Anderson became increasingly aware of how deeply Ray’s words and her journey with Winn were affecting her. “I was very aware that the understanding that I was getting while I was filming was shifting,” she says. “To be in nature to that extent in all versions of themselves, to immerse myself in the thought process of someone who’s experienced that level of trauma, trying to deal with it.”