This song went to number one and was the theme of one of the most successful musicals of all time…

This week in 1978 the third song from one of the most successful movie soundtracks of all time was released – it quickly shot to number one on the Billboard Hot 100.

The vocalist was already an established singer on his own merit, particularly famous for his distinctive falsetto voice.

It was the title track and theme for the smash hit film and is synonymous with the movie and pop culture of the era…

Can you guess what this sing-a-long tune is?

Listen to Frankie Valli’s “Grease” below: