Acting veterans Clark Gable, Spencer Tracy and John Wayne were paid to promote smoking during Hollywood's "Golden Age", it has emerged.
The stars received huge cash sums from their film studios to advertise tobacco, according to researchers at the University of California at San Francisco.
One of the key documents uncovered by the researchers was a list of payments for a single year in the late 1930s detailing how much stars were paid by American Tobacco, the makers of Lucky Strike.
Actresses Carole Lombard, Barbara Stanwyck and Myrna Loy were handed $10,000 (GBP5,500) - equal to around $150,000 (GBP83,300) in modern money - to endorse the brand.
American Tobacco also sponsored The Jack Benny Show from the mid-1940s to the mid-1950s.
The authors of the study conclude the deals led to a rise in the number of young people who took up smoking in that era.