Invasion of the Body Snatchers (1978)
Invasion of the Body Snatchers is a 1978 science fiction thriller directed by Philip Kaufman, and starring Donald Sutherland, Brooke Adams, Veronica Cartwright and Leonard Nimoy. Released December 20, 1978, it is a remake of the 1956 film of the same name, which was based on the novel The Body Snatchers by Jack Finney. The plot involves a San Francisco health inspector and his colleague who discover that human beings are being replaced by aliens. The duplicates, who appear to be perfect copies of the persons replaced, but are devoid of any human emotion, attempt to install a tightly organised, conformist society.
More at Wikipedia.