Quentin Tarantino has been filmed losing his cool with a paparazzo at the Sundance Film Festival.

Tarantino – who is heading up the jury at this year’s event – appears surprised to find a cameraman waiting for him as he leaves a coffee shop - which is strange given that the small town in Utah is always swarming with paps come festival time.

In what may or may not be a set-up, the director repeatedly asks the lensman, "What's going on here?," before launching an attack on his camera.

When the pap challenges the director to hit him, Tarantino seems to think better of indulging in an on-camera punch-up and walks away.

But not before insisting that he would be "wupping" the guy's "ass up and down the street" if he wasn’t being filmed.

Smack-down or set-up? Watch the video below & decide for yourself...