Two local boys playfully got into it on “Conan” last night, where Brookline-bred host Conan O’Brien discussed his shared hometown with Cambridge ruffian Casey Affleck. Wait, Cambridge … ruffian? That’s what the “Out of the Furnace” actor would have you believe, cracking jokes about being from “the slum, the gutter, the actual gutter” before finally claiming Cambridge as his home.

He started the tough talk after O’Brien said he could walk from Brookline into Boston, saying, “but we don’t let you walk there, we kick you out” (we? Yeah right). In turn, the host ribbed Affleck about “rough Harvard gangs” roaming Cambridge, including the med school and law school gang. When O’Brien asked Affleck why he doesn’t have a Boston accent, the actor said he has a “weird voice” and people thought he was foreign growing up.

As for all that Boston tough talk, maybe the Affleck boys and Matt Damon are so deep into the proposed Whitey Bulger movie that they’re forgetting which side of the river they’re actually from. Or maybe they’re still confused from “Good Will Hunting.” Or “The Town.” Or “Gone Baby Gone.”