Bear Grylls will host a new Amazon series being billed as the "toughest global outdoor multi-sport endurance race on Earth".
The TV adventurer will host Eco-Challenge 2019, in which teams of men and women will tackle challenges over a more than 300-mile race course.
The rebooted series is produced by Mark Burnett, who is responsible for the US versions of The Apprentice and Shark Tank.
It was one of a host of announcements made during the Prime Video Presents event in London.
Speaking on stage in London, Grylls said: "This is a race like no other, you never leave a man behind. If somebody quits, the whole team is out.
"It's hard and unforgiving but fosters a spirit that we are in this, one and all.
"It's the ultimate race with the ethos many are called but few are chosen, and seeing those teams go to the limit is compelling.
"I get such a kick out of bringing to millions of people this spirit of endeavour, never giving up and loving and protecting our world."
Burnett told the audience: "The typical race is around 300 miles non-stop. It is teams of four, men and women in each team.
"If any single person quits, the entire team is disqualified. It's lots of pressure, people train for about a year, they need to know mountaineering, ocean kayaking, repelling, caving, mountain biking, non-stop.
"This eats the Iron Man for breakfast, it's like doing 10 or 12 Iron Mans back to back. It's an expedition with a stopwatch."
He added: "It's very global, 50 or 60 teams of or from 20 or 25 countries.
"This is the best of the best. The women members of the team tend to be the strongest because they are much better at knowing how to manage the team, when to rest, it's a matter of managing how much sleep to have.
"The teams that try to go without sleep collapsed."
Model and actress Cara Delevingne was among the other talent present.
Speaking about her new Amazon show Carnival Row, she said she was drawn to "the social, political themes" of the project.
She said: "Immigration, classism and racism, important themes that need to be addressed more and more."
She added: "It's fantasy that we have never seen before."
Her co-star Orlando Bloom added: "It's a sort of Dickensian, steam punk, Victorian world with these remarkable and beautiful mythical creatures.
"When I got to Prague and saw the set they had built I was blown away, it was truly remarkable. The world they have built, the epic size of the story they were creating."
John Krasinski appeared at the panel on a break from filming to hint at details of the second series of Jack Ryan.
He announced new characters including his "new female counterpart, a friend and enemy of Jack, played by Noomi Rapace".
He added: "She has been amazing, we are lucky to have her. And from House of Cards we have Michael Kelly, playing my CIA boss."
Jennifer Salke, the head of Amazon Studios, also announced new show Wheel of Time, a multi-book fantasy story by Robert Jordan.
She said: "It is an epic sprawling world where magic exists but only women can use it, and we think it's particularly timely."
Salke also announced Amazon has signed an exclusive deal with Good Omens creator Neil Gaiman, saying: "You will see more of him and his incredible brand."
Gaiman, whose novel American Gods was turned into a television series, will exclusively create further content for Amazon Prime Video.