The actress/director also co-wrote the screenplay with Ung and is producing the project, which the filmmaker tells local newspaper In Phnom Penh will be told from the child's perspective.
"The intent of this project is not to revisit the horrors of the war but to bring to the screen characters that people around the world will identify with and empathise with, and help to teach people about this country that I love and respect, and the Cambodian culture and family life I so admire," Ung said.
Jolie, who has two other adopted children and three biological kids with husband Brad Pitt, has already touched down in Phnom Penh to check in on the progress of her two longest-running charities, the Maddox Jolie-Pitt Foundation and the Maddox Chivan Children's Center, organisations which Jolie says her son will take over when he is older.
First They Killed My Father: A Daughter of Cambodia Remembers is slated for release on internet streaming site Netflix in late 2016.
- WENN