WWE Superstar R-Truth performed a surprise set of material before the Insane Clown Posse concert Friday in North Carolina … and he used some less than PG words before rapping.

Truth hit the stage at Tremont Music Hall in Charlotte not long after ICP teased fans about their surprise opening act on social media — with the wrestler receiving a big “Woop Woop” before his set.

We’re told Truth was brought on stage by JCW Champ Weedman and performed 3 tracks … including “Me, Myself and I” and “Rep My City” — describing the first as, “some real deep sh*t.”

The whole thing was part of ICP’s “Marvelous Missing Link Tour,” which also features P.O.D.

Best part of the video is the end. Truth busts out some of his famous dance moves.

Check it out!