When renowned wildlife producer Mike Gunton approached “The Lion King” director Jon Favreau about collaborating on a documentary, the director, who had never made a doc, immediately said yes.

It was 2022, and Gunton, an executive producer at BBC Studios Natural History Unit, wanted to “supersize” his “Dynasties” series about vulnerable or endangered species, and make a multipart doc focused on one species. At the time Favreau and Gunton were working together on the first season of “Prehistoric Planet,” a natural-history show that tells the last days of the dinosaur using CGI.

“It wasn’t like I wanted to do a documentary,” said Favreau. “It was more that I really enjoyed working with Mike and his team. They went from my world — the digital world and then I went to their world, which was the documentary.”

Over the course of four years, Favreau and Gunton worked with a production team that included producers, researchers, editors and cinematographers Simon Blakeney and Sophie Darlington to create National Geographic’s “Lion.”

“Mike had the ambition of following a single pride of lions in a way that had never been done before, and it meant hanging up all the tools that I was comfortable with, like CGI, and going completely analog,” said Favreau. “We made a rule that we were not going to do any digital augmentation, not paint things out, and not manipulate the footage.”

The four-part series follows a lion cub named Kio, who faces loss, exile and fierce rivals in a fight to survive and become a king. Filmed in Kenya’s Maasai Mara, “Lion” is the first natural history production to document a lion’s complete journey from cub to king. The crew, including local Kenyan filmmaker Faith Musembi, logged nearly 1,400 filming days across 52 shoots — the most time ever spent in the field exclusively following a single pride. It was a daunting project that Gunton knew Favreau would be interested in executive producing, and not just because he had directed both the 2019 live-action remake of the animated classic “The Lion King” and “The Jungle Book.”“When we first met, Jon told me that he had been using “Dynasties” as a reference for how (lions) moved, how they behaved, and what their little micro movements were while making “The Lion King,” said Gunton. “So, there was an immediate simpatico between us because he was fascinated by the logistics, the grammar, the style, the approach, and all the storytelling techniques in a documentary like ‘Dynasties.’”

To find a main character for “Lion,” the crew initially followed two prides in the Maasai Mara. Family trees were drawn up. Each lion in both prides had its own identification card, where details down to the whisker spots were logged. The production team relied on a network of local field guides to help them track the lions, who could be hard to find when hidden in bushes or mile after mile of long grass. Eventually the crew could identify up to 50 lions from different prides by name and family relationships. “We were following prides, and within them there were male cubs, female cubs, big, powerful queens, and also other kings,” said Guton. “Any one of these characters could have ended up being the star. But quite quickly we found this female lion and her cub we called Kio.”Finding the main character for the series was a relief. It could also have been a nightmare, given that 50% of lion cubs don’t make it to adulthood. Through parts of the rainy season, Kio couldn’t be followed by the crew as the plains in the Maasai Mara became impassable. At other times, Kio and his brothers were hardly seen for weeks. Every check-in with the field team started with a question: “How’s Kio — is he alive?”“You really have to surrender yourself to what fate had in store,” said Favreau. “We didn’t have any recourse to change the outcomes. I’m used to writing and creating shots and creating moments. Not knowing whether the lead character that emerged was going to survive through each rainy season was harrowing.”As the series exec producer, Favreau helped take approximately 1,000 hours of footage and turn it into a comprehensive, four-hour story. Like Disney’s “The Lion King,” Nat Geo’s “Lion” also tells the coming-of-age story of a male lion, which, Favreau said, was a fluke.“Less than half lion cubs survive to adulthood, so we didn’t know what was going to present itself,” said Favreau. “What ended up emerging was the story of this one young, small lion that kept surviving and prevailing and growing and emerging and eventually reaching adulthood and becoming a leader in his own right. So, it did echo a hero’s journey type story and ended up echoing a lot of Disney heroes and felt like it connected very much with ‘The Lion King.’ The fact that things played out the way that they did was not something we could have anticipated.”Although the story is reminiscent of “The Lion King” and Hans Zimmer composed the score for “Lion,” the series is real-life drama.“It’s not jaws and claws nor is it saccharine,” said Gunton. “It’s true. It’s what happens in nature. It’s sometimes tough. It’s sometimes beautiful. It’s sometimes heartwarming. It’s sometimes shocking. But nobody’s going to say, ‘Oh, that’s been Disneyfied,’ And nobody’s going to say, “Oh, that’s a bit tough. That’s a bit horrible. That’s a bit bloody.’ I think we’ve got the line pretty right.”“Lion” premieres on Aug. 19 on National Geographic and streams on Disney+ and Hulu on Aug. 20.“Lion” is produced by BBC Studios Natural History Unit for National Geographic. Favreau and Mike Gunton executive produce the series. Jane Atkins is series producer, and Simon Blakeney is co-executive producer. For National Geographic, Janet Han Vissering and Tom McDonald executive produce.