"The Big Unknown" is a song by the English band Sade released in 2018. The song is featured in the motion picture Widows directed by Steve McQueen and centered on four women forced to pull off a robbery to pay a large criminal debt left behind by their late husbands. The film, which was adapted from the UK crime series of the same name, stars Viola Davis, Daniel Kaluuya, and Robert Duvall. Along with the songs by Sade and Nina Simone, the official soundtrack to Widows features an original score written by Hans Zimmer.

Sade are an English band, formed in London in 1982 and named after their lead singer, Sade Adu. Three members, Paul Anthony Cooke, Stuart Mathewman, and Paul Spencer Denman, are from Hull in the East Riding of Yorkshire. Its music features elements of soul, quiet storm, smooth jazz and sophisti-pop. All of the band's albums, including compilations and a live album, have charted in the US Top Ten.