Actress Naomie Harris, director Justin Chadwick pour hearts into 'The First Grader'

Naomie Harris has rubbed shoulders with the biggest of stars and relaxed in the comfort of the best star trailers that Hollywood has to offer. But for her latest film, "The First Grader," which opened Friday at the Broadway, the working conditions couldn't have been any different.

Going from movie star luxury on the "Pirates of the Caribbean" movies to a hole-in-the-ground toilet surrounded by corrugated iron for privacy is a big adjustment. Not that Harris would have had it any other way.

"It's a very different experience," she said. "There is a small band making a film, a tight unit, and we all draw so much closer, like a family unit, a much more collaborative unit."

Portraying a teacher in a village in Africa meant that she became a real one in Kenya, teaching children who weren't acting but simply learning. They had never seen a movie or a television before, much less a camera, so every shot of the film is a genuine teaching moment. After weeks of cultural immersion to study her Kenyan accent, she was placed in a school for filming with authentic students and extras from the community and cast and crew also from the region.

"I loved the idea of really getting to immerse myself in another culture and get away — live among the community," Harris said.

"I was introduced to 80 children … as their teacher. It was the most challenging thing I have ever done. I learned it's a really hard job. It was really, really challenging, but I have to say it is one of the most rewarding things I have ever done. It was amazing, that light bulb moment when they got the idea of what I was teaching."

When Kenya announced in 1993 that it was offering a free education, pupils flocked to schools to take advantage of the opportunity. One candidate, Maruge (played by Oliver Litondo in the movie) was in his 80s but was willing to do anything he could just to learn how to read.

Harris plays the teacher, Jane Obinchu, who was moved by the elderly man's tenacity and desire to learn and supported his efforts despite opposition by parents, administrators and the government.

The film follows Maruge and his young fellow pupils as they learn together and form bonds while the elderly man occasionally reflects on the violent past of his Kenya and the price he paid as a young man for its freedom from England.

Director Justin Chadwick ("The Other Boleyn Girl") knew he must tell the story of the nation's and Maruge's mostly ignored past to help give context to his simple desire to read.