Angelina Jolie reveals what it was like working alongside two of her sons on her latest drama, “First They Killed My Father”, a biographical thriller based on Loung Ung’s memoir.

Speaking with ET Canada’s Cheryl Hickey at this year’s Toronto International Film Festival, the 42-year-old actress and mother of six explains the “joy” she felt working alongside her son Maddox, 16, who helped executive produce the project, and her other son Pax, 13, who served as an on-set photographer for the film, which Jolie also directed.

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“It was a joy,” Jolie says of working with her two eldest children, whom she shares with her ex, Brad Pitt. “I want them to have a strong work ethic.” She continues, “When I looked over and I saw [Maddox] and Pax working with the other crew […] it was just wonderful.”

The subject of the film was especially significant for Jolie’s first son Maddox who was born in Cambodia, which also serves as the setting for the film. Jolie explains it was great for her son to be able to work “with his countrymen.” Adding, “I think [that] helped him to grow and evolve in a way that I couldn’t do myself. His country had to teach him.”

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Jolie’s latest film follows the life of human-rights activist Ung, who grew up as a child solider during the Cambodian genocide. “I hope that when people see this film, they don’t see the war and the suffering, but they really get to know a Cambodian family and a beautiful culture,” Jolie says.

Bringing her six children to the film festival, Jolie jokes “packing for me is like a military exercise.” However, she notes it’s getting better, adding, “They’re getting older now, so the older ones help the younger ones, and actually they’re quite efficient.”