Continuity mistake: When Chris is taking a walk with the priest Damien, she throws her cigarette to the ground, but in the next shot it's back in her hand again. (01:21:30 - 01:22:06)
Trivia: Author and writer of the book and script William Peter Blatty has a cameo early in this film. He plays the producer trying to have a word with director Burke Dennings on the movie set before Burke turns his attention to Chris MacNeil. William Peter Blatty is the middle eastern-looking guy with the black hair and moustache, which is natural since his mother is originally from Lebanon.
Revealing mistake: When Father Karras sprinkles holy water on Regan, they forgot to paint her ear lobes and it looks terrible. (01:32:30)
Answer: When it cuts to Chris MacNeil's PA, Sharon, listening to the radio it's only for about 20 seconds, and all we hear is a voice which presumably belongs to a random radio host or guest who is in the midst of offering motivational advice. This short scene serves to show Sharon's tension with what's going on in the house.
Super Grover ★