Helen Folasade Adu, known professionally as Sade Adu or simply Sade, is a Nigerian-born British singer, known as the lead vocalist of her band Sade. One of the most successful British female artists in history, she is often recognised as an influence on contemporary music. Her success in the music industry was recognised with the Officer of the Order of the British Empire in 2002, and she was made Commander in the 2017 Birthday Honours.

"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.