Robert De Niro looks like he’s among the legions of folks who walked away from the Lindsay Clancy murder trial thoroughly impressed with her lawyer, Kevin Reddington … because we have video of them chatting it up.

TMZ obtained footage of Robert and Kevin talking up a storm Wednesday at the CBS Broadcast Center in Manhattan … crossing paths before separate appearances on “CBS Mornings” … and they sure looked chummy.

Kevin even put his arm around the Oscar-winning actor … and we’re told they may have even taken a picture together at some point.

Lindsay’s lawyer appeared on the morning talk show and made an impassioned plea for folks to leave her ex-husband, Patrick Clancy, alone amid mounting conspiracy theories.

Kevin said … “I just think that it’s horrific what this man has been going through, and he’s entitled to move on with his life.”

Speaking out against conspiracy theorists who claim Patrick framed Lindsay for the grisly deaths of their three kids, Kevin said his “gut-wrenching” 911 call should put any doubt to rest.