When Michael slapped Kay in Hotel Washington after Kay's abortion / unholy and evil denouncement, Kay's reaction to the slap was either very good acting or Kay had no idea the slap was coming....
Kay gasped, jerked and staggered, falling back on the couch, in a heap [left handed slap from right handed Michael who was still holding the cigarette in his right hand!]
The above perhaps is not dissimilar to the below
I seem to recall, Marlon Brando improvised slapping Al Martino to “act like a man†Johnny Fontane's confused reaction was real as the slapping was not in the script
John Marley was not aware that a real horse head had been substituted for the prop used during rehearsals Jack Woltz's screams were real when he saw the severed head of the horse which was obtained from a dog food factory
