TOM BRADY plays himself in a ridiculous new video on FunnyOrDie.com.  He's at a sporting goods store looking for clothes, and the salesman can't get over Brady's Boston accent . . . even though he doesn't have one.

Then Brady gets angry because no one recognizes him . . . and one customer thinks he's Matt Damon.  The whole thing is an ad for Under Amour, but it's still kind of amusing.