Madonna talks about her adoption struggle

Madonna may have walked the red carpet in a glittering Chanel gown to launch her new film at Cannes on Wednesday, but the nature of I Am Because We Are is in stark contrast to the high-octane glamour of the Croisette. A documentary about the problems caused by poverty and the unrelenting spread of Aids in Malawi, the film could never have garnered so much attention were it not for the Queen of Pop's involvement (she is the film's writer and executive producer ). But, for once in Madonna's movie career, the attention is justified.

She could easily have made an indulgent vanity piece, tearfully cuddling photogenic orphans for an hour and a half. And, inevitably, there is some of that. But her on-screen presence is kept to a minimum and her narration is used mercifully sparingly so that the whiny anglicised tones don't grate too much.

Madonna wrote the script herself, so a tolerance for cloying sentimentality is required : 'People often ask me why I chose Malawi. I tell them, I didn't. It chose me'. On the plus side, her very personal involvement makes the film feel like an intimate journey - although viewers hoping for an insight into the shenanigans surrounding David Banda, the Malawian child she adopted in October 2006, will be disappointed. He features briefly, but the film doesn't go into the controversy that followed her decision when British tabloids tracked down David's father.

Although hugely emotive, the film is not perfect by any means. A noisy montage of images of destruction from around the world feels amateurish, as if the first-time director Nathan Rissman is trying to cover too many bases and appeal to the YouTtube generation. But the film works much better when focusing on the tales of ordinary people. Rissman has elicited some incredible stories of indescribable suffering: a woman who must be subjected to a sexual ordeal in order to be 'cleansed' after the death of her child, a boy who had his genitals cut off in a brutal superstitious ritual, and a dying mother who wonders what will become of her soon-to-be-orphaned son.

This rich material makes for a completely absorbing film. Certain scenes, such as women and children literally dying of Aids in front of the camera, drew gasps from the shocked audience in the screening room at Cannes. It's impossible to tear your eyes away from the screen. Not that the film portrays Malawian people as innocent victims of circumstances beyond their control. Rissman doesn't shy away from the culture of drinking, crime and violence that is prevalent in the country.

Together, he and Madonna have made a shocking and incredibly moving film that is much more than an extended Comic Relief appeal. If Madonna wants us to see her as more than the gyrating, gym-obsessed Queen of Pop, she has succeeded powerfully .

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