(TMZ)For all the non-believers, Here is photographic evidence there IS a Tupac sex tape.

Tupac received oral sex from a mystery woman back in 1991 … and it was all caught on tape. The 5-minute video shows Tupac in a living room, holding a cocktail in one hand and a blunt in another.

An unreleased Tupac song is playing in the background, as the rapper sings along, wiggling his hips — all the while getting serviced by the woman.

Check out the photos: