A foster girl notorious for scaring off prospective new foster parents finally meets her match in the upcoming film adaptation of Katherine Paterson’s The Great Gilly Hopkins, starring Kathy Bates, Octavia Spencer, and Sophie Nélisse as Gilly. Though Paterson’s Newbery Honor Book was originally published in 1978 by T.Y. Crowell, it is being adapted into a feature-length film for the first time.

Gilly Hopkins has lived in foster care her whole life and has built up a tough outer shell, determined to making herself as unlovable as possible. She clings to the hope that she will one day be reunited with her birth mother, played by Julia Stiles in the film. When Gilly goes to live with a new foster parent, Maime Trotter (Bates), and her family as a last option before being sent to live in an institution, her usual tactics for being kicked out from a household don’t work as planned, and the unconditional love and affection she experiences with the Trotters catch her off-guard.

It’s not the first time Paterson has had a book adapted to screen. In addition to several TV movie adaptations of her books and stories, Bridge to Terabithia was made into a feature length film in 2007. Though Paterson wasn’t directly involved with the writing of the screenplay for The Great Gilly Hopkins, the project was kept in the family: it was written by her son, screenwriter David L. Paterson. He has previously adapted several of his mother’s works to stage and also wrote the script for the 2007 Bridge to Terabithia – in fact, fittingly, the story was partially inspired by the death of one of his childhood friends.

As he told PW: “My mom was fairly comfortable with my adapting without her input. She knew my objective was to tell her story – not to change it, improve it, or alter it. Gilly was a great book. We knew it would be a great movie.”

Paterson said he did face some difficulties during the screenwriting process, but it had little to do with the book’s content or the fact that the book was written in a different era. “The biggest challenge for me was dealing with how much of the book takes place in Gilly’s head – her thoughts, her schemes, her revenge plans,” he said. He explained that he decided against using a voiceover or having the character talk directly to the camera. “I didn’t think either of these would be believable or enjoyable for the audience. So creating scenes that needed to take place in the real world to show Gilly’s feelings and motives without changing the storyline were the most challenging elements of writing the film.”

While the film may hold particular appeal to parents who remember the book from childhood, the casting of Sophie Nélisse, who starred in the movie adaptation of another novel for younger readers, The Book Thief, may also attract younger viewers. And The Great Gilly Hopkins isn’t alone in being made into a movie decades after publication. While uncommon, other middle grade and YA books published in the past have been refashioned into films in recent years, including an adaptation of Judy Blume’s Tiger Eyes, R.L. Stine’s Goosebumps series and, most recently, Roald Dahl’s The BFG.

Whatever the audience demographic is for the film come October, Paterson’s script has already been praised by his most important critic, whom he reports was “very pleased with the final draft.” Katherine Paterson herself has been very vocal in promoting the film through social media, urging readers who love the book to spread the word and “make Gilly the little movie that hits it big!”