Original song written and composed by Barry Gibb, Maurice Gibb, and Robin Gibb; from the 1977 film "Saturday Night Fever"
"If I Can't Have You" is a disco song written by the Bee Gees in 1977. The song initially appeared on the Saturday Night Fever soundtrack in a version by Yvonne Elliman, released in November 1977. The Bee Gees' own version appeared a month later as the B-side of "Stayin' Alive". Wikipedia