Crews was out at Craig's when we asked how the guys in Hollywood's newest celebrity feud should settle their beef ... a beef that started when Bieber dissed Diaz's fighting style on social media.
Of course, Diaz fired back on the "TMZ Sports" TV show -- saying, "F**k that fool."
But Terry -- who stars in "Brooklyn Nine-Nine" -- says the time for talk is OVER and it's time for the guys to settle it like men ... IN THE OCTAGON!!!!
Hey Justin free advice ... don't even think about it.