The Mexican stars in new movie No as a businessman who helps bring democracy to Chile in the late 1980s while the country is in the grip of oppression under dictator Augusto Pinochet.
Bernal is frustrated that many human rights crimes in his native continent still go unpunished, and he is a keen supporter of Amnesty's No To Impunity drive, which is pressing for authorities in South American countries to come clean about their murky past.
Posing for photographs while holding a campaign board, Bernal says, "There is a lack of justice still. Pinochet, for example, never went into a court house. He was never tried. He died with millions of dollars in a United States bank account. But he is just one of the many reasons why the issues raised in the film remain relevant today."