On August 26, 1978, Frankie Valli’s “Grease”—reached the #1 spot on the Billboard Hot 100. the second chart-topping hit from the album of the same name.

The 1960s was the final decade in which the musical hits of Broadway were routinely and successfully adapted by Hollywood into big-budget screen versions. West Side Story (1961), My Fair Lady (1964), The Sound Of Music (1965), Funny Girl (1968)—all of these movie musicals were among the biggest critical and commercial hits of their era. But while the early part of the subsequent decade brought successful adaptations of Fiddler on the Roof (1971) and Cabaret (1972), Hollywood had all but given up Broadway by the middle of the 1970s.

And then, in 1978, Paramount Pictures placed a big bet on a small musical called Grease and came up with not just an enormous hit movie, but a true pop-cultural phenomenon that included one of the most successful original motion picture soundtrack albums in music history.

The two Grease numbers that preceded Frankie Valli’s title tune as singles were the #1 hit “You’re the One That I Want,” a duet by the film’s co-stars John Travolta and Olivia Newton-John, and the #3 hit “Hopelessly Devoted to You,” by Newton-John alone. The cast ensemble performance of the song “Summer Nights” would also become a Top 10 single, making it the only one of the Grease soundtrack’s four hit songs that actually came from the original Broadway show. Musically, the original Broadway show Grease hewed very close to its 1950s setting, featuring songs that were clear nods to period styles and stars—songs like “Greased Lightnin,'” “Beauty School Dropout” and “Hand Jive.” When it came time to film the movie version, however, a whole new slate of songs was added, including “You’re The One That I Want,” “Hopelessly Devoted to You” and the song that hit #1 on this day, August 26, in 1978, “Grease.”

“Grease” was the second solo chart-topper for Frankie Valli, who made his name in the early 1960s as the lead vocalist of the Four Seasons and later scored several major hits as a solo artist, including the #2 hit “Can’t Take My Eyes Off Of You” (1967) and the #1 “My Eyes Adored You” (1975). “Grease” was written for Valli by Barry Gibb, who accomplished a remarkable feat of his own with the song. When “Grease” completed its second weeks at #1, it was the 26th week at #1 for Barry Gibb as a songwriter in 1978. In addition to “Grease,” the other #1 hits of 1978 written by Gibb were: “How Deep Is Your Love,” “Stayin’ Alive” and “Night Fever,” all performed by the Bee Gees; “(Love Is) Thicker Than Water” and “Shadow Dancing,” performed by brother Andy Gibb; and “If I Can’t Have You,” performed by Yvonne Elliman on the Saturday Night Fever soundtrack.