How Angelina Jolie Ended Up Playing an Elephant: Inside the Casting of 'The One and Only Ivan'

Angelina Jolie, The One and Only Ivan

Danny DeVito as a dog! Sam Rockwell as a gorilla! Chaka Khan as a baseball-playing chicken!

Who would have guessed that one of the most emotional performances of the year would come from an elephant voiced by Angelina Jolie? And yet, you will no doubt find yourself getting a bit misty as a particularly poignant pachyderm named Stella delivers a monologue about the power of memory in Disney+'s latest offering, The One and Only Ivan.

The movie is adapted from Katherine Applegate's Newbery Medal-winning children's book -- itself based on a true story of the real-life Ivan -- about a 400-pound gorilla living in captivity at a shopping mall and grappling with questions of where he comes from and where he truly belongs. It's there at the Big Top Mall that Ivan learns about the importance of friendship and the power of visualization, largely through Stella's speeches beautifully penned by screenwriter Mike White.

"I wasn't really looking to do a kid's movie," says White, who is better known for adult fare like Beatriz at Dinner and Enlightened, though he also scripted The Emoji Movie. "But someone sent me the book and it packed so much more of a punch than I was expecting. It was such a complex, melancholy and poetic book for something that was meant for kids."

Unbeknownst to White, Jolie had a similar read on it. Her daughter, Shiloh, recommended The One and Only Ivan to her and, after reading it, Jolie began inquiring whether a film was in the works. She signed on both as a voice actor and a producer. "I tried to push it to stay as true to the book as possible," Jolie tells ET. "I think it's very, very special, especially with the environmental issues -- the destruction of these natural habitats and poaching -- and we have young people who are activists now and are aware of these issues."

"Angelina really wanted to make sure that we were getting the pain of the characters -- that they are in a prison, in a sense -- and making sure that we are being honest emotionally about what that means," White says. "And I was glad to have her advocating for that." He chuckles, "At the same time, it's a heavy theme, and you realize you're making this for young kids. I remember when I was a kid watching Bambi's mother die and being inconsolable and not being able to move forward. So, you've got to remember that this is for kids."

Angelina Jolie on the set of 'The One and Only Ivan.' (Disney+)

The One and Only Ivan finds a dose of comedic relief and a plethora of tender moments in its ensemble of circus animals: There is, of course, the gorilla artiste Ivan (voiced by Sam Rockwell), and his best friend, Bob the dog (Danny DeVito), along with Snickers the poodle (Helen Mirren), Murphy the bunny (Ron Funches) and a baseball-playing chicken called Henrietta (the legendary Chaka Khan).

The final role to fill was that of Frankie the perpetually anxious seal, who is voiced by White himself. "I have a feeling it was Thea just sitting there like, 'Who's good to be a neurotic obsessive?' Then looks across the desk at me like, 'Well, we got it right here.'"

Considering White started working on the script some six years ago, there was no way for him to know who would eventually bring each animal to life. He credits the director, Thea Sharrock, with the seamless voice casting. "Of course, there's always a period once you get the actors to adjust for them and let them bring their own stuff to it," White says.

Like, for instance, when Henrietta coos, "Ain't nobody love you better," a line clearly inspired by her voice actor. "We played around with some of the iconography with Chaka," White confirms. (With a laugh, he adds: "I feel weird calling her Chaka. Ms. Khan? I don't know.") Sharrock also had her actors record their dialogue in groups together to promote collaboration.

"Normally you're on your own with the director, but it made a huge difference," Mirren says of recording with DeVito and Rockwell. "All three of us were in the room together, and you can play off each other. You can improvise. You can laugh at each other -- because Sam and Danny were always making me laugh."

"Yeah, it was great. I didn't know that, you know, so I didn't wear pants the first day," DeVito jokes.

Jolie, meanwhile, recorded with young co-star Brooklynn Prince, who voices the Big Top Mall's newcomer, a baby elephant named Ruby. "I said, 'Hey, why don't we wear elephant onesies in ADR?'" Prince recalls. "And she was like, 'Sure.' So, I go home and I'm like, 'Mom, please buy me and Angie elephant onesies!' And my mom was like, 'I'm buying an elephant onesie for Angelina Jolie?!' And on the day, Angie shows up and she pulls out her elephant onesie and we rocked them the rest of the day."

"How can you say no to that?" Jolie grins.

The One and Only Ivan is streaming on Disney+ on Aug. 21.