Listen to They Don't Know online. They Don't Know is an English language song and is sung by Jon B. They Don't Know, from the album R&B - 100 Hits - The Greatest R n B album - 100 R & B Classics featuring Usher, Pitbull and Justin Timberlake, was released in the year 2013. The duration of the song is 4:33. Download English songs online from JioSaavn.