The One and Only Ivan director says Disney+ film keeps the spirit of the book alive

And director Thea Sharrock has said that it was absolutely crucial for the film to keep the spirit of Applegate's book alive, even if there were a few changes to the narrative.

Speaking exclusively to RadioTimes.com, Sharrock (whose previous film Me Before You was also a book adaptation) said, "For me the most important thing was to hold onto the spirit of the book and the spirit of what I felt the book was really about.

"I learnt very quickly that there were certain things that happen in the book that the fans of the book absolutely live and die by.

"Those are the pinpoints that you have to get right, you have to really understand what it is that everyone else loves about it, and you have to get those right."

The film is by no means a straight adaptation of the source material, with Sharrock explaining that it was important for her and screenwriter Mike White to inject a bit more drama into the script and to expand on some of the characters.

"In the book dramatically speaking, until right at the end, nothing really happens, so in a way the hardest job Mike White and I had was to create a sense of drama," she explained.

"We did that by bolstering up some of the characters that were very small in the book, and also crucially we thought of it like a prison escape movie - and in order for that to really land properly, we needed to have an escape that was foiled and then didn’t work.

"That isn’t in the book, and is probably the biggest moment that isn’t in the book, isn’t a parallel. In the book you don’t need it because you have this incredible narration by a gorilla and that voice feels so close to you."

Sharrock said that she became attached to the project after reading the book with her children - who she claimed were the perfect age to enjoy it - and falling in love with the novel.

"I read it with them [her kids] and it was really profound, my appreciation of how Katherine Applegate wrote the book and managed to pitch a story that was so emotional, so educational, so inspiring and yet so profoundly happy in a way that I could appreciate and enjoy, and my kids could at the same time.

"I knew that sometimes we were enjoying the same thing at the same time, and I also knew that there were times that I was understanding something on a slightly different level to what they were understanding, but she’d managed to pitch it in such a way that I don’t think she ever leaves anybody out.

"So it was a really gorgeous story to get to know genuinely alongside my kids and then to be given the opportunity and privilege to take the story one step further and make it into a film was amazing and a joy."

• The One and Only Ivan true story – discover the fascinating real events that inspired the movie

The One and Only Ivan premieres exclusively on Disney+ on Friday 21st August 2020. You can subscribe to Disney Plus for £59.99 a year (or £5.99 a month). If you’re looking for more to watch, check out our TV guide.