Vivica A. Fox Goes to War with 50 Cent Over 'Gay Stuff' (VIDEO)

Vivica A. Fox fired the first shot at 50 Cent, and now he's launching missiles back at her -- after Vivica hinted he has issues with "gay stuff."

Vivica, who's guest starring on "Empire," was on "Watch What Happens: Live" ... and Andy Cohen brought up Fiddy's infamous Instagram re-post ... which claimed "Empire's" ratings decline was due to "gay stuff."

Check out her dramatic pause before blurting out ... "The pot calling the kettle black, is all I'm gonna say."

She tried to backpedal a little, recalling good times when she dated 50 -- but then did even more damage by questioning his magazine cover shot with Soulja Boy.

50's fired back the way you'd expect, writing on IG ... "Now she thinks I'm gay because I let her lick my Ass. LMAO."