Aamir Khan spent more than two decades as one of India's most admired movie stars, appearing in a string of socially conscious but mainstream films.
Now he has gained even more fame as the host of a popular weekly television show that is calling attention to some of the country's longstanding social problems.
Mr. Khan's show, Satyamev Jayate, or Truth Alone Prevails, is taped in front of a live audience, and is something more than a talk show but short of 60 Minutes. Mixing Oprah-style interviews on a couch with short reports from the field, it tries to shine a spotlight on festering issues like dowries, domestic violence and the indignities of the caste system.
In just three months, the Sunday morning show has become a national phenomenon, distributed in seven languages and drawing a cumulative audience of nearly 500 million, according to Star India, the network that broadcasts it.
One of the early programs, in May, provided a vivid example of the show's influence. Mr. Khan, 47, highlighted a seven-year-old sting operation by two TV reporters who had broadcast film of more than 100 doctors offering to illegally abort female fetuses. While the legal cases against them languished in India's notoriously slow courts, the doctors continued to practice medicine.
But just days after Mr. Khan featured the topic on his show, the top elected leader from the State of Rajasthan, where the journalists did their investigation, met with Mr. Khan and promised to have the cases transferred to special courts that expedite decisions.
That kind of swift response has made Mr. Khan -- variously described as India's Oprah Winfrey, George Clooney or Bono -- increasingly sought after by policy makers, social advocates and others who see him as a savior or champion for their causes. In addition to meeting with the chief minister of Rajasthan, he testified before a committee of Parliament about the country's health care system after he did a program on medical malpractice. And last week he met with Prime Minister Manmohan Singh to press for a government ban on the practice of having human waste cleaned and carried away by people born into the lowest rungs of the caste system.
He also has a weekly column in The Hindustan Times, takes calls on a weekly national radio show and is frequently interviewed on prime-time TV news shows.
"Mr. Khan is doing the nation a service by raising important issues which need greater public debate," said Dr. K. Srinath Reddy, president of the Public Health Foundation of India, which is financed by the government and nonprofit organizations like the Bill and Melinda Gates Foundation.
Shyam Benegal, a respected TV and film director and a former member of the upper house of Parliament, said Mr. Khan had done what many others had failed to do -- reach the Indian mainstream by using Bollywood tropes in the service of larger causes. His shows always include musical performances and frequently show him crying as he interviews his guests.
"This is effective because Aamir Khan is a film star," said Mr. Benegal, who once made shows for the state-owned broadcaster, Doordarshan. "And he is a pretty good P.R. man for himself, as well. And all those things help."
Star India, owned by the News Corporation, is India's largest network, and Mr. Khan's show is simulcast on Doordarshan and a handful of other channels. His fame has helped attract sponsors like India's largest cellphone carrier, Airtel, and the foundation arm of one of its largest companies, Reliance Industries.
In an interview earlier this month, Mr. Khan likened his approach for the show to his 2007 movie,Taare Zameen Par or, literally, "Stars on Earth." The film, which he directed and starred in, told the story of a family's and school's inability to meet the needs of a dyslexic child.
"If I tell you I am making a film on dyslexia, how many people are going to walk into the theater?" he said in a discussion at the Taj Land's End, a five-star hotel frequented by Bollywood stars. "No one will walk in: 'Oh, come let's watch a movie about dyslexia.' So, I have to tell you it's a film about childhood and children."
In the same way, he said, Satyamev Jayate does not announce in advance the subjects he intends to cover.
There is little in Mr. Khan's upbringing to suggest he would end up hosting such a show. He dropped out of college to pursue his movie career and his first breakout film, in 1988, was a popular Bollywood musical in which his character elopes with his girlfriend because their families do not approve of their relationship.
About a decade ago, however, Mr. Khan began to go down a different path. In the 2001 Oscar-nominated movie Lagaan: Once Upon a Time in India, Mr. Khan played a villager in colonial India who challenges a British regiment to a cricket match to determine whether his village must pay an extortionate land tax, or lagaan.
Some entertainment industry analysts trace the change to his relationship with Kiran Rao, an assistant director on Lagaan who became Mr. Khan's second wife. Ms. Rao is known for eclectic interests and for making films that do not hew to the well-worn Bollywood formula.
Since Lagaan, Mr. Khan has starred in and or produced movies that deal with issues like political corruption, indebted farmers and India's regimented higher education system. Most popular Indian actors like Shah Rukh Khan and Salman Khan, who are not related to Mr. Khan but with whom he is often compared, have largely shied away from such subjects.
"It's hard for people to remember now that in the 1990s, that he was a huge star -- one of the three Khans," said Rachel Dwyer, a professor of Indian cultures and cinema at the University of London. "It's in this decade that he has remade himself."
Mr. Khan said he did not see Lagaan as a turning point for his career. But he acknowledges that Ms. Rao, whom he described as "full of life," has helped him become less insular.
While his show has won much praise, it has also been criticized for its sometimes simplistic treatment of complicated subjects. The Indian Medical Association has protested its portrayal of doctors, which it says casts doctors as money-grubbing and unprofessional based on a few errant examples.
Other critics have charged that the show is too meek about identifying culprits. For example, it did not name the doctors accused of offering the illegal abortions.
Mr. Khan said he never intended to make an investigative show similar to 60 Minutes and argued that he was having a much bigger impact by putting troublesome issues in front of mainstream audiences in a way that seeks to shame them out of their apathy. "We are not mincing our words," he said, but added in Hindi: "Our attitude is not to blame this or that person. We are all to blame. First, you have to understand that."
Both Mr. Khan and Uday Shankar, the chief executive of Star India, declined to provide financial details about the show, other than to say Mr. Khan's production company is paid 35 million rupees ($630,000) for each of the 13 episodes of the first season, which ends on Sunday. Both say they would like to do another season, but will wait a few months to make a decision.
In the meantime, some of Mr. Khan's supporters have suggested that he run for elected office, which has often served as a sinecure for Indian film celebrities. Mr. Khan denies any interest in politics.