They should be the happiest boys in Afghanistan. Zekeria, Ahmad and Ali have been plucked from their home in war-ravaged Kabul to star in "The Kite Runner," the long-awaited Hollywood film of Khaled Hosseini’s bestselling novel.

It is expected to be one of the year’s biggest box office hits, but the boys will not be joining the ranks of Hollywood’s child-star millionaires. Two were paid over $17,500 each while the other got around $13,700, their parents lost their jobs and they now fear they will be kidnapped or hounded out of Afghanistan because of a rape scene in the film, which will be released later this year.

Executives from DreamWorks picked 12-year-old Zekeria Ebrahimi, Ahmad Khan Mahmidzada, 11, and Ali Dinesh, 11, from 2,000 Kabul schoolchildren last summer to play the key roles in Hosseini’s haunting tale of betrayal and redemption in Afghanistan’s dark years of mujaheddin strife and Taliban terror.

The novel, which has sold more than 3 million copies, describes the relationship between Amir, the son of a powerful Kabul businessman, and Hassan, whose father is a faithful family servant. Hassan, played by Ahmad, is forever defending Amir, played by Zekeria, from bullies.

Amir is determined to win a kite-flying tournament to secure his father’s approval. But on the afternoon of the contest Amir finds Hassan being beaten and raped by a local thug. He does nothing to help his devoted friend. Their lives are shattered.

The boys will be invited to the film’s American premiere, but it is its subsequent release in Afghanistan that fills them with apprehension.

Huddled around the wood-burning stove of a small concrete house on a muddy road in west Kabul, Zekeria, Ahmad and their parents said they felt exploited by Hollywood.

“I want to continue making films and be an actor but the rape scene upset me because my friends will watch it and I won’t be able to go outside any more. They will think I was raped,” said Ahmad.

His careworn father, Ahmad Jan, fears his family will be shunned by fellow members of the Hazara population. The Hazaras have been persecuted for more than a century in Afghanistan, most brutally under the Taliban who massacred them for their Shi’ite Muslim faith.

“People will come and arrest us and put us in jail. They will think we’ve made the Hazara look bad,” he said.

The lives of the children’s families reflect the turmoil portrayed in the film. Ahmad’s father was shot and wounded during internecine fighting after the Soviet forces that had invaded in 1979 withdrew a decade later. Seven close relatives were killed during the conflict.

Shortly before Zekeria was born, his father was killed by a stray mujaheddin rocket as he left home to buy some medicine. The family fled to Peshawar in Pakistan, where they lived as refugees.

According to the boys and their parents, they loved acting in the film. Their three months spent filming in China were the first time they had felt truly safe and free to enjoy the things most western children take for granted, such as fairground rides.

Zekeria and Ahmad want to leave Kabul for the West. “We want to study in the United States. It’s a modern country and more safe than here. If I became rich here I would be worried about security. It’s dangerous to have money because of the kidnapping,” said Zekeria.

The problem is that they have not been paid enough to make the new life they have glimpsed. Ahmad’s father has lost his second-hand goods shop and is now unemployed after three months in China. Zekeria’s uncle and guardian Noorullah lost his IT job at the ministry of rural affairs.

Zekeria and Ahmad’s families have put aside the film earnings for the boys’ future. But the parents of their co-star Ali Dinesh, who was paid just £7,000 for his performance as adult Hassan’s orphaned son, used his money to repay a family debt.

“Seven thousand pounds is not a lot of money,” said Ali’s adult brother Ashraf. “Our friends in the movie asked us how come we agreed to do it for so little . . . but we had already signed the contract.”

In a statement Paramount Pictures, which bought DreamWorks last year, praised the actors and said it had sought to respect the culture of the people portrayed in the story.