Mira Nair has lived in Kampala, Uganda for over 27 years, but hadn’t heard of Phiona, Uganda’s female chess champion, until a Ugandan at Disney told her of the inspiring story.

In this new behind the scenes featurette for “Queen of Katwe,” Lupita Nyong’o and David Oyelowo, the film’s stars, and director Nair express how moved they were by the story and by their lead actress, newcomer Madina Nalwanga.

“It just put things into perspective,” Nyong’o says with tears in her eyes. “I felt very privileged and honored to be able to share these children through this.”

“Queen of Katwe” is based on “the colorful true story of a young girl selling corn on the streets of rural Uganda whose world rapidly changes when she is introduced to the game of chess, and, as a result of the support she receives from her family and community, is instilled with the confidence and determination she needs to pursue her dream of becoming an international chess champion.”

“Queen of Katwe” will hit U.S. theaters on September 23. It was also recently announced that the film will mark its European Premiere as the Gala Selection of the BFI London Film Festival, which runs from October 5-16 this year.

“Africa is teeming with amazing people who in spite of their, at times, difficult lives, manage to remain full of joy and hope,” said Oyelowo of the announcement. “This is a story where the impossible is made possible through family, mentorship, encouragement, hard work, and faith, all things we can aspire to. It is a story that speaks to anyone and everyone, and I am so proud to have it screen in my hometown.”

Watch Nyong’o, Nair, and Oyelowo go into more detail about the film in the video below.