Brooks' directorial debut, You Light Up My Life, had become successful largely on the strength of its title song, which as recorded by Debby Boone had spent ten weeks at #1 on the Billboard Hot 100 in 1977.
[1] Brooks then approached Atlantic Records president Jerry Greenberg with the intent of having the If Ever I See You Again theme song and other songs from the film recorded by Roberta Flack (Flack has stated that she had been offered "You Light Up My Life" prior to the Debby Boone recording: (Roberta Flack quote:)"Some people whose opinions I respect very much suggested I should do it...but the song reminded me of too many other things that I had heard or sung and I just didn't like it [although] I think [for] Debby Boone ['You Light Up My Life'] was perfect".
With a track from Flack's 1977 Blue Lights in the Basement album: "I'd Like To Be Baby To You", as B-side, "If Ever I See You Again" was released as a single on 21 April 1978 - a month before the film's premiere - to debut the Billboard Hot 100 dated 20 May 1978 at #87 (the same chart ranked the Blue Lights in the Basement single: the Donny Hathaway duet "The Closer I Get to You" at its #2 peak for a second and final week).
With the film If Ever I See You Again quickly proving a massive flop, Flack's single was left to fare on its own merit, and did in July 1978 spend three weeks at No.
However Flack did reach the Top 20 of the Hot 100 with two duets: "Tonight, I Celebrate My Love" with Peabo Bryson (#16/ 1983) and "Set the Night to Music" with Maxi Priest (#6/ 1991).