Tom Brady just gave every Buccaneers fan a heart attack -- pretending to cut off his finger while filming a video ... but don't worry, it's all fake!
TB12 made the joke while hanging out with celebrity chef Nick DiGiovanni recently.
In the clip that the GOAT shared to his Instagram page, he asked Nick how to toss a knife on the cutting board for the camera.
"Just take it, and put it into the board," Nick said
Brady did just that -- but then suddenly screamed, "F***!"
The CGI is pretty good .