So I'm watching Friedrich (Nosferatu) Murnau's Tartuffe (1925) and this odd bit happens...
A young man has just been thrown out of his grandfather's home by a housekeeper who is trying to steal his inheritance.
He turns and runs across the street...
and comes right up to talk to the camera:
but it's a silent movie; he can't actually talk to the camera so you get an intertitle instead:
It's a bit like when Bugs Bunny says "of course, you know this means war..."
Talking to the audience wasn't unknown in live theater then, but this is the earliest film that I've seen where an actor playing a character addresses the camera.
Gertie the dinosaur interacting with onstage Winsor McKay doesn't count. Gertie was playing herself.