The actor begged Academy members to start recognizing people of color for their contributions via an ad he took out in The New York Times -- just in time before voting kicks off for the Primetime Emmy Noms June 13.

He writes, "Dear Hollywood, please let this be the year we finally embrace change. The year we truly find equity and see artists of color represented across not just one category but ALL categories."

JL acknowledges academy members might be tired of hearing buzzwords like "inclusivity" and "diversity" ... but he encouraged them to move beyond just talking about it.

John says taking action is pretty simple, writing ... "There are hundreds of prolific non-white artists who deserve to be considered for awards this year, not because they are simply ... Black, Brown, Indigenous, or Asian, but because they are truly great ... exceptional artists who have achieved that greatness with a foot on their neck for far too long."

He says he hopes this change could mark the start of a new era -- a catalyst to inspire the next gen of minority artists who can finally see themselves onstage or on camera.

John himself has put in some serious work breaking diversity barriers in Hollywood. He bagged his first Emmy in 1999 for Outstanding Performance in a Variety or Music Program for his comedy special "Freak." He's also received 3 other Emmy noms, most recently for 2019's "When They See Us." So he's been one of the most visible actors of color.