Bong, 47, and Swinton, 56, spill details about the film’s most unusual elements.

1. Okja is a combination of pig, manatee and dog.

Bong looked to a variety of real animals for inspiration. The pig, of course, “was important, because pigs are very sophisticated and clean,” he says. Okja also shares physical attributes with the manatee, which “looks like the most kindhearted and fragile animal.” The super pig’s playfulness put Swinton in mind of her four dogs, particularly her oldest, Rosie. “I started to call her Okja,” the actress says. “She’s completely Okja.”

2. A puppeteer brought Okja to life on the set.

Bong had a life-sized mock-up made of Okja, which a performer would manoeuvre during shooting. “We had a ‘stuffie’ for every part of her body,” he says. “That was the only way for the post-production [special effects] work to be accurate. Mija’s always hugging and grazing Okja’s face. [The puppet] doesn’t smell too pleasant, but it looks lovely.”

3. Jake Gyllenhaal’s creepy nature host was inspired by real people.

Gyllenhaal’s Johnny Wilcox, a washed-up TV zoologist, was loosely modelled after the late British TV hosts Johnny Morris and Jimmy Savile, the latter of whom police say committed hundreds of sex crimes, the majority of them against children. “There’s a sort of tradition of family entertainers who are quite bombastic, but also very often sinister,” Swinton says. “We all remember as children watching these people and [thinking], ‘There’s something a little bit glitchy about the over-the-top enthusiasm’. ”

4. Tilda Swinton’s character has hints of Ivanka Trump.

As the head of the Mirando Corporation, Lucy Mirando starts an initiative to create giant pigs to remedy global hunger. The bloviating character is the manifestation of “fake ‘wokeness,’ ” Swinton says.

Shooting Okja last summer, Swinton couldn’t help but see some parallels between Lucy and Ivanka Trump. “I was standing in costume, watching her [on TV] at the Republican [National] Convention in a very similar look like, ‘Oh, we’re doing the same thing’, ” Swinton says. “She wasn’t exactly an inspiration – she was more of a nightmare realisation.”

5. The toughest scene to film featured two Tildas and cigarettes.

Challenging scenes to shoot included a giant chase inside an underground shopping mall and a parade where activists expose the Mirando Corp’s animal cruelty. But the most intricate was a seemingly simple encounter between Lucy and her twin Nancy (also Swinton), when they bump their cigarettes to light one. “You’ll get the angle right and then Bong will be like, ‘Actually, you’re supposed to be Lucy, but you used Nancy’s voice,’ ” Swinton says. “And you’re like, ‘Ugh!’ ”