LL Cool J appears as himself in a scene halfway through the film where he auditions for Rick and the other Krush Groove management team. In that scene, it is presumed that LL Cool J is an unknown. However, near the beginning of the film, when Sheila E. is performing "A Love Bizarre" in a club, the name "LL Kool J" (sic) can be seen written on the chalkboard behind her on stage. The chalkboard is still seen during other performances before LL Cool J makes his appearance.
When the fat boys are singing all you can eat in the when they go to the cashier with the food if you look in front of the restaurant you will see a crew member standing at the door making sure nobody goes inside. You can also see people looking inside while the scene is being filmed.