"The best moment is when Rajinikanth first appears on the screen: the excitement and enthusiasm almost reach boiling point when the letters S-U-P-E-R-S-T-A-R appear one by one on the silver screen. It's his nickname and everyone calls him that. The audience is already shouting and cheering, but the noise reaches fever pitch as the fans get their first glimpse of the actor. Shreds of paper, called dollars, are thrown into the room."

Anthropologist Roos Gerritsen was recently awarded her doctorate for her research into the mixture of idolisation and politics in Tamil film stars' fan clubs.

Some sixty million people live in the state of Tamil Nadu in southern India. The state has its own language, Tamil, and a large film industry. In the Kodambakkam district of its capital Chennai, approximately 100 films are shot every year and Rajinikanth (61) is the king of "Kollywood" cinema.

In 2007, he was the second best-paid Asian film star, only beaten by Jackie Chan; he has twenty thousand official fan clubs each with between ten and thirty members on average, besides countless unregistered admirers.

Women hardly feature at all in this public adoration; it is male territory. "On the day of a premiere, they'll be up early to queue for tickets. They dance and light tiny candles, holding them up to the screen as a tribute. They pour milk and beer on pictures of Rajinikanth. The first time you watch a film, it's not about understanding the story, it's about the experience. Then you go another ten times to learn the songs."

And there is much singing and dancing in Tamil films, although they differ from the Bollywood productions that we are more familiar with. "Those are set in an urban environment and are often about an elite world with rich people."

Chennai films are usually set in the country. "The heroes are from a lower socio-economic class; Rajinikanth does not come from a wealthy family either."

Gerritsen has a favourite Rajinikanth film too: "It's Badshaa from 1995, in which he plays a man who turns his back on his gangster life in Bombay and becomes a poor but honest rickshaw driver in Tamil Nadu. In the film, he sings a song about being honest and doing good, a very happy song; people refer often to it."

There are murals and billboards depicting film stars and politicians all over Chennai. The world of entertainment flows into that of politics, and the fan clubs have a decisive part in that. "They start as part of youth culture: boys who can get free tickets or who want to impress the girl next door. Initially, the films are the main thing: you feel closer to the star and you can to talk to others about the latest gossip." Gradually, politics begin to feature in the life of a fan. "Many members think: I've been a fan for such a long time, spend money on billboards and do social work; now I want some power too."

Fans can wield quite considerable influence. Back in the seventies, film star M. G. Ramachandran turned his ten thousand fan club members into senior party officials and with their support, he remained the most important administrator in the state until his death in 1987, while in his wake several of the senior party officials managed to acquire political clout.

But it does not always work. The clubs wanted Vijayakanth, the other major star alongside Rajinikanth, to become a politician and he had similar ambitions. "He is still in politics, but his fans have not managed to keep their positions in his party, because most of them are poor young men from the country. A politician needs money and his fans don't have that. The party set up another fan club to give disappointed fans a platform, but they are not really active anymore."

Rajinikanth has taken a different approach: "He has not founded a political party, but at elections, he announces for whom he will be voting. He uses his status and does plenty of charity work. Many fans are frustrated because he won't found a party. They don't get very much return on the time and money they have contributed, but resigning from the club is too drastic for them. On the other hand, not all fans want him to set up a party. One of his most devoted fans said: "Please don't let him go into politics; it will only corrupt him." Some fans truly love Rajinikanth."