In 1964, a western lowland gorilla was captured in what is now the Democratic Republic of the Congo and brought to the United States to live among humans.

But he quickly grew too big for a family home so he was moved to a concrete enclosure at a shopping centre in Tacoma, Washington, where he spent the next 27 years of his life.

It is an extraordinary story, which was spotted by author Katherine Applegate and inspired her 2013 best-selling book The One And Only Ivan, in which she fictionalised the story, changed the human characters and told it from Ivan's point of view.

Now a long-awaited film adaptation is here, blending live action and CGI and boasting an all-star cast, including Angelina Jolie, Bryan Cranston, Danny DeVito, Dame Helen Mirren and Chaka Khan.

"One of my children read the book and said that they loved it," explains Jolie, who voices the elephant Stella and also serves as a producer on the film.

"So I read it and we talked about why it was special and why it meant so much to them and I started to pursue where it was and if it was being made and started to get involved.

"It had really started to become a light fun kids action film, a simpler story, but everybody involved really understood that it's hard, it's not a light film, it deals with heavy issues.

"It's charming and fun and full of life but it's deceptive in the packaging, so I thought very, very important."

The film finds Ivan as a 400lb silverback gorilla who lives in a small enclosure as the main attraction at a circus in a shopping centre, owned by Cranston's character Mack.

When a new baby elephant arrives, Ivan begins to reassess his life and the film reckons with what it means to keep animals in captivity.

Jolie said: "I think all of us older people will appreciate it for many reasons but I know this young generation is really very aware of what is happening in the world to our natural habitats, to these animals, what is happening in Congo and losing ground, what is happening to the gorillas, the elephants, and they are angry.

"They want to really be clear about what kind of treatment is appropriate, what kind of captivity is appropriate, being against poaching, the preservation of natural habitats, so I think this represents them, and I think that is strong for them to see today that their actions can make change."

While Mack could be reduced to the villain of the piece for keeping these animals in captivity, Cranston is keen to show humanity to the circus owner who shares an unusual bond with the animal.

"I saw him as a man who has flaws," the Breaking Bad star explains, "but is also attempting to make things right.

"Ivan was like a child to him so he wasn't about to abandon his child, so he wanted to figure out how to embrace the fact that he's now a full-fledged silverback gorilla and how do I live with that.

"We talked about it and I pitched the idea that Mack wears a wig and at one point the wig flies up and he's bald and it embarrasses him and I also had a stomach pad to make him a little bigger and a girdle so that when he's doing his showman thing he's wearing a girdle.

"Those kind of things were personal vulnerabilities that he didn't want people to see. He was presenting himself as someone but it wasn't really him and at the end it came full circle and he embraces who he truly is and he's happy and proud to see that Ivan has moved into the next chapter of his life."

The film's British director Thea Sharrock, who is best known for her work in theatre and has previously helmed film Me Before You, as well as episodes of Call The Midwife and The Hollow Crown, said it was important to strike a balance between uplifting family fare and the seriousness of animal captivity.

"It was a big concern from the beginning," she admits, "to not make it feel like a documentary. That has been made already.

"Also this is not just any studio, it's Disney, so we definitely knew there was a tone that we had to get right.

"We worked endlessly, even down to how big the bars are so on camera they would have the right feel. In certain scenes there are no bars to be seen whatsoever, and in other moments we have chosen very carefully when the presence of the bars are there so that they are a constant reminder.

"It's not easy when your leading character is behind bars for 80% of the movie so you have to hold at its heart that he creates a dream to get out.

"We also made the choice to have next to no green in the movie, so that when you get to either Ivan's flashbacks from when he's a kid, which we made as green as possible and made as like the Congo as possible, or the very end when he gets to where he needs to go, we made that as green and as lush as possible.

"We wanted to capture the heartfelt spirit of the book, which was the most important thing, but there are also some very important big issues captured within the book that my kids, who were nine and 10 at the time, connected with it on an emotional level, so that had to be there too."

The One And Only Ivan is on Disney+