Survivalist Bear Grylls joins forces with some of Hollywood’s most beloved celebrities for a new season of his outdoor adventure series, Running Wild With Bear Grylls, returning to National Geographic on Sunday January 19. WEEKEND chats to the adventurer about his A-list guests, battling extreme environments and channelling his own fears.

There’s only one person who could get Captain Marvel star Brie Larson to scramble across a body of water with a crocodile closely eyeing her up and Call Me By Your Name star Armie Hammer to drink milk from the nipple of a goat. And it’s not some big-name Hollywood director putting the A-listers through their paces for a film... but Bear Grylls.

Oscar-winner Larson and Hammer are among the guests Grylls, 45, has lined up for the new series of his National Geographic survival skills programme Running Wild, in which he takes celebrities on two-day trips into the wilderness.

The series kicks off again on January 19, starting with Larson’s adventure across the Pearl Islands in Panama. But even Grylls, who doesn’t seem fazed by anything out of the ordinary in the wild, admits Hammer’s goat episode is among the memorable moments.

“I just thought we’d just squeeze the teat and we’ll get some milk and it will give us some energy for the rest of the journey, but he dived in for it and it was pretty funny,” he says matter-of-factly.

Asked what else is in store for viewers, he rattles off a list of exotic edibles like it’s a restaurant menu.

“We had some snakes. We had scorpion. We had rat.”

And he continues: “I managed to start a fire with urine, which was a new experience for me. I’d always wanted to see if I could do that, and that was pretty cool with Dave Bautista from The Avengers to start a fire with pee, which was quite fun.”

It’s not quite everybody’s idea of entertainment but for Grylls, the son of politician and former Royal Marine Commando Mickey Grylls, the outdoors is his second home.

He says: “Wilderness food is never going to be pretty and it’s probably never going to be very tasty, but it will keep you alive, give you some energy, give you a new experience, and give you something to laugh about with your family when you’re back home. This season has loads of that.”

The TV star, whose real name is Edward, was nicknamed Bear by his sister when he was one week old. He says the series, which will also feature the likes of Magic Mike star Channing Tatum and model and actress Cara Delevingne, is meant to be an empowering experience for those who tackle it.

“Scary at first, but empowering when they’re finished, and that’s the part of Running Wild that I love; seeing that sense of pride and achievement in these guests when they finish a journey,” he says.

The stars who come on the show appear because they want to, Grylls explains.

“These stars don’t need the money. They don’t need the fame. They’re coming because they want the experience to learn these skills and to have an empowering journey, and that’s the heart of Running Wild.

“We take people that really want to have that experience, and when you take people like that, they’re always excited; they’re always up for it, and that allows us to push it with what we do and it makes for a good episode,” he says.

He says Hammer has “become a good friend” since filming and that the person who surprised him most was Delevingne.

“She has something like 45 million or 50 million Instagram followers, many of these Hollywood stars don’t have followings like that. And her story has been such, one of struggle and battle to get to where she is, that many of her followers don’t really know that.”

He adds: “I think the great strength of Running Wild is that you have time on these journeys to get to know the real person and to hear their stories. It’s not like a chat show where you’re just trying to tell a funny story for two minutes.

“When you have to spend two days together, you really get to know someone. You have to face some fears. You have to keep moving forward and never give up, and that’s been her life story. I think that was the surprising one but a real joy for me and a pleasure to do.”

He’d love to have someone like tennis ace Novak Djokovic as a guest too.

“I’d love to get him on the show maybe for the next season and do one in Serbia and hear his story and his great love for the country,” he says.

Last year, Grylls, who is also Chief Scout, was recognised in the Queen’s Birthday Honours with an OBE for services to young people, the media and charity.

In 2015 he made headlines when former US President Barack Obama featured on Running Wild.

Grylls served for three years as a Trooper in 21st SAS Regiment, part of the UK Special Forces Reserve, where he was trained in combat survival, demolitions and close quarter fighting, before he climbed Mount Everest at the age of 23 and guided a team circumnavigating the British Isles on jetskis.

And while fear doesn’t seem to be a word that’s in his vocabulary, he says it’s about resilience which he likens to “a muscle”, adding: “I think the more you train it, the stronger that gets. And we’re such a tight-knit team, and we know how to do our job, and my job is to keep these guests safe and help them to overcome their stuff, and definitely I still have loads of fears in everyday life.”

Skydiving, for one, he says, is something that he still thinks twice about. He explains: “I find skydiving really hard. I broke my back whilst I was in the military in an accident and spent a year in and out of military rehabilitation and thought I’d never walk again properly.

“So I still find that emotionally really hard, mentally really difficult, still to this day when that door opens of the plane, but I’ve learned that the best way to overcome fear in life is to move towards it, go straight towards it, embrace it.

Running Wild With Bear Grylls airs from January 19 on National Geographic, starting with Brie Larson’s adventure across the Pearl Islands in Panama.