Madonna's gardener , Nathan Rissman directs her new documentary

"Nathan Rissman basically did everything for me," the singer – who produced and narrated the film, I Am Because We Are – told PEOPLE. "He was my gardener. He was my carpenter. He rerouted the electricity in my house. He looked after the children. And he started making home movies of my children. And they were amazing."

"Nathan has the ability to instill trust in people," Madonna said from the stage after Thursday's screening. "And so many of the children started to open up to him ... I've ended up with what I consider to be a very good film and a beautiful son."

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