The 27th Day is a 1957 science fiction film from Columbia Pictures. It was directed by William Asher, produced by Helen Ainsworth, and the screenplay was written by John Mantley, who also wrote the original novel. The cast includes Gene Barry and Valerie French.
This was a low-budget film with little action and few special effects, with the shot of the alien spacecraft being reused footage of the flying saucer from Earth Vs. The Flying Saucers. Instead the story focuses on dialogue.