Joseph Fiennes discusses cousin Ranulph’s diagnosis: 'His next big adventure is battling Parkinson's'

Watch: Jospeh Fiennes opens up about about his explorer cousin

Britain’s greatest explorer, Ranulph Fiennes, was just 27 years old when he first traversed Canada’s wilderness by its rivers in 1971. Now, over 50 years later, Fiennes is embarking on a very different adventure; that of living with Parkinson’s disease.

In a new documentary series, the adventurer, along with his cousin — the Emmy-nominated Joseph Fiennes — journeys along the waterways of British Columbia. There are moments when he’s unable to take part in certain activities, such as climbing mountains, because of his impairment.

For Joseph, the fact Ranulph was contending with Parkinson’s disease during filming added to the emotional weight of the adventure, which is being released as the two-part series Fiennes: Return to the Wild.

"Ran is of the generation that doesn't get emotional," the actor tells Yahoo UK. "You can't get an emotional when you're spending 90 days in very inhospitable circumstances or you are in the army. You have to think very laterally.

"Ran’s next big adventure is battling Parkinson's, and that's something that came out of this trip. It was very moving and insightful and incredibly brave of him to admit and talk and open up and hopefully, to champion others to face this bravely, like he is."

The documentary — a follow-up to their previous odyssey down the river Nile — sees the two Fiennes share many poignant moments in which they reflect on life. In one scene, they stand upon a bridge above a river and Joseph comments: "Like life, we’re just passing through."

"Too quickly," replies Ranulph.

Read more: Prince of Wales pays tribute to Sir Ranulph Fiennes

"A lot of those poignant moments come from the sort of the enormity of the space you're in, where you're slowly dwarfed by how beautiful and precious our world is, and how fragile it is," Joseph says.

Watch a clip from Fiennes: Return to the Wild

"We all know about global warming, and upon reflection on that, we see how fragile we are as humans and how quickly it all passes, and to not to take it for granted – not the earth and not ourselves and not each other."

Considering the two Fiennes cousins are among the most successful people in their respective fields, it’s hard not to wonder what runs in their blood – especially when you add that Joseph’s brother is the Oscar-nominated actor Ralph Fiennes.

"It's a peculiar gene pool, I guess," Joseph says. "I don't know quite what it is. I feel, speaking for myself, incredibly lucky to do the thing I'm passionate about and so, to have parents that might champion you in the thing that you're passionate about, it's been a great leverage in my life."

When it comes to comparing trophy cabinets with his older brother, though, there’s no competition. "He has me on that," he continues.

"I wouldn't even pretend to go there. But we don't tend to talk shop. Rather like this relationship in Fiennes: Return to the Wild, it's about family and more poignant and pertinent discussions beyond the business."

Fiennes: Return to the Wild premieres on National Geographic on Sunday 26th May at 8pm, followed by the second episode on Sunday 2nd June at 8pm.