Two members of Sly, Slick and Wicked -- a '70s R&B group -- filed the lawsuit, and in the docs they say "Suit & Tie" samples their song, "Sho' Nuff" ... which was released in 1973. It's no lightweight hit ... none other than James Brown produced it.
The band members say Justin's record label, Universal Music Group, paid to sample the song -- however, never got the rights to the vocal performances in that song. Their bottom line ... we did the singing, but we didn't get paid.
Making matters worse ... the SS&W guys say they also didn't get paid when UMG licensed "Suit & Tie" for a Bud Light commercial.
They point out Justin's song was HUGE -- 3 million copies sold, and 92 million YouTube views -- and they want their piece of the pie ... from UMG, Anheuser-Busch, and other publishers and producers of the track.