The Liberty King is a film released in 1998, during the events of Grand Theft Auto: Liberty City Stories and it can be seen on DVD covers in Grand Theft Auto IV and Grand Theft Auto V. It is directed by Joe Jones and Jack Jones, with the soundtrack written by Ryan JJ Armit. It is produced by Love Productions, part of the Love Media conglomerate owned by Donald Love. It cannot be viewed by the player.
The poster has the GTA III art of Donald Love. It's not clear whether the story is about Love himself or if it was just an Easter Egg of sorts.
It is possible that Joe and Jack Jones are a parody of real life film directors, The Coen Brothers.