For some, it’s a recurring nightmare, the dream that they’re back in school again. For Naomie Harris, star of the Toronto Film Festival favorite The First Grader, it was a job requirement.

At first, Harris, who plays an elementary-school teacher in a classroom with dozens of Kenyan children and one 84-year-old villager, was puzzled by director Justin Chadwick’s request that she actually teach class. With a younger brother and sister, she didn’t feel she needed to prove she could work with kids. But the lesson proved a blessing.

For the first of her three-week crash course as a teacher in Africa, Harris, 34, was close to tears: Her pupils sat stone-faced, despite her attempts at conversation and humor. But she soon realized their reaction was no fault of her own.

“Culturally, for them, to look an adult in the eye is disrespectful,” she says. “To engage an adult, especially a teacher, in a dialogue is also disrespectful. Teachers and children there don’t have the jokey kind of relationship that’s more common in the West.

“For that first week, I was crying to my stepdad on Skype, thinking they hated me. But you have to be patient and gentle, and slowly they started opening up.”

The movie is inspired by the real-life story of Kimani Ng'ang'a Maruge, an octogenarian veteran of the Mau Mau uprising who forced his way into the classroom when, in 2003, the Kenyan government offered free education to all citizens. His efforts were initially ridiculed, but his desire to read proved stronger than the taunts and threats.

Harris plays Jane Obinchu, the teacher who welcomed him into her schoolhouse and defended his right to stay. Grader is as much the story of Obinchu as Maruge, the now-famous student who became the unlikely face of Kenya’s education movement when government officials learned of his quest.

To Harris, however, the heart of the movie is the children, who warm up to Maruge – forcefully played by Oliver Litondo, in his first big-screen appearance since 1984's Sheena: Queen of the Jungle – as slowly as they warmed up to her. It took three weeks, but she knew she’d won them over when they began toying with her hair, playfully punching her and holding her hand.

Harris previously starred in 28 Days Later and Pirates of the Caribbean, and admits that craft services weren’t nearly as elaborate on the set of her latest film. (Actually, there weren’t any craft services.) But that hardly discourages her from promoting it.

“This is an important film,” she says. “I’ve worked in blockbusters before, and this one doesn’t have an 18-million-pound budget. But it’s important that small, independent movies have a place in the industry. [This one] has an amazing message. Most movies don’t.”

The First Grader is now playing at the Opera Plaza Cinemas, and at the Shattuck Cinemas in Berkeley. For tickets and showtimes, click here.