"The Voice" judge Cee Lo Green is calling BS on Mariah Carey and Nicki Minaj's fiery feud -- telling us, we're in L.A. ... practically EVERYTHING is fake in this town.

Cee Lo had just finished lunch in West Hollywood yesterday when we asked if he thought Nicki and Mariah's "Idol" fight was legit -- and he said, "This is Hollywood, California. Hardly anything's legit."

As for a possible "American Idol" ratings boost following the Nicki/Mariah fight -- Cee Lo says he's not worried, claiming, "I'm not intimidated. I think it's entertainment for everybody."

From TMZ.com

Thumbnail via TMZ.com