Ray J Shocks 50 Cent by Becoming Human Billboard at Promo Event

Ray J showed up late to his own party with 50 Cent -- but when he finally arrived, he made it worth the wait. Ray knows how to make an entrance ... when money's on the line!!!

Fiddy and Ray were supposed to show up together at the recent L.A. meet-and-greet with fans. The plan was they'd shake some hands, take some pics and promote their respective brands -- 50 with his top-shelf Branson Cognac, Le Chemin Du Roi Champagne and RJ with his Raycon earbuds.

Well, 50 was on time, but Ray ended up rolling in about 90 minutes after things started. Not to worry though, he came prepared ... literally dragging in his own Raycon poster and stand into place for maximum visibility in photos.

The whole scene was kinda ridic, and 50 probably summed it up best, saying ... "What the Ray J is going on?!?"