Please buy your music.
When Bee Gees manager Robert Stigwood was producing a movie about a New York disco scene, the working title for the film at that time was Saturday Night. Stigwood asked the group to write a song using that name as a title, but the Bee Gees disliked it. They had already written a song called "Night Fever", so the group convinced Stigwood to use that and change the film to Saturday Night Fever.
The string intro of "Night Fever" was inspired by "Theme from A Summer Place" by Percy Faith, according to keyboardist Blue Weaver when he was performing it one morning at the sessions and Barry Gibb walked in and heard the new idea for this song.
As Weaver explains the history behind this song:
'Night Fever' started off because Barry walked in one morning when I was trying to work out something. I always wanted to do a disco version of Theme from A Summer Place by the Percy Faith Orchestra or something - it was a big hit in the Sixties. I was playing that, and Barry said, 'What was that?' and I said, 'Theme from A Summer Place', and Barry said, 'No, it wasn't'. It was new. Barry heard the idea - I was playing it on a string synthesizer and sang the riff over it.