Youngsters who watch films in which actors are seen smoking are three times as likely to take up the habit, according to research.
There is a call for films featuring smoking to be given R-ratings
Research in health journal The Lancet said smoking in movies can actually encourage non-smokers to follow their screen idols.
The findings have been both welcomed and rubbished, with some experts saying there are too many other factors which influence whether teenagers do go on to smoke.
The US study has also led anti-smoking group Glantz to call for films where actors are seen smoking to be given an adult R-rating.
Bollywood stars have already launched their own campaign to persuade film-makers to avoid using smoking in films.
The latest research, which was conducted at Dartmouth Medical School, New Hampshire, studied 2,063 children between the ages of 10 and 14 who had never touched a cigarette.
Bollywood stars have become anti-smoking campaigners
In 1999, the children were asked which films they had seen from a list of 50 from the past decade.
It was then calculated how many incidents of smoking they had witnessed, and split into four groups depending on their exposure level from zero to 531 occurrences and 1,665 and 5,308.
Between one and two years later 10% of the overall group had started or tried smoking, with the majority of those coming from the group who had seen more films scenes featuring smoking.
Taking into account other factors such as peer pressure and rebelliousness, it was calculated that children were three times more likely to take up the habit if they were in the group who watched the highest amount of screen smoking.
The investigation also concluded that 52% of children involved took up smoking because of the influence of screen stars.
But media theorist Paul Levinson of Fordham University, New York, dismissed the findings as inaccurate for not looking at how important other factors were on smoking.
Tobacco giant Philip Morris USA said the industry was not to blame for the amount of smoking seen in films as it did not condone the product placement of tobacco products.
It said directors and producers needed to be careful about depicting smoking in youth-targeted films.