What book in the bible does Jesus say something about the souls of entertainers being dark as a moonless night or something similar to that.
As a long time actor and a Christian I assure you that there is no such verse in the Bible.
What I suspect you are thinking of is one of the many verses in which Jesus condemns hypocrites and hypocrisy. Here is a search that will give you many of them. They are talking about those who pretend to be virtuous on the outside but inwardly are corrupt.
The claim is sometimes made by those that dislike entertainment of all kinds that the word 'hypocrite' derives from the word for 'actor', and this is in a sense true (it comes from French and Latin and ultimately from Greek), but the word did not mean that at the time when the Bible was translated to English, and the original Bible verses are not referring to actors, but to 'hypocrites' in the sense that we understand the word today.
As already communicated, outside of the calling people "hypocrites," Jesus did not talk about the theater. But, here are a few related tidbits to add to what has already been said.
Paul likens the one who does not love to the bronze amplification 'gongs' of the theater (1 Corinthians 13:1). See "Sounding Brass" and Hellenistic Technology (https://members.bib-arch.org/biblical-archaeology-review/8/1/5)
It is likely that Jesus was very aware of the theater. The major metropolis of Sepphoris was only a few miles north of Nazareth. Jesus lived at the height of an economic boom that would have provided a carpenter from Nazareth with ample work. The 4000 seat theater of Sepphoris was constructed at the time of roughly 20 AD. It is here that Jesus may have picked up the word "Hypocrite."
In Augustine's Confessions - He speaks about the theater (book 3.2) “ I was much attracted by the theatre, because the plays reflected my own unhappy plight and were tinder to my fire. Why is it that men enjoy feeling sad at the sight of tragedy and suffering on the stage, although they would be most unhappy if they had to endure the same fate themselves? Yet they watch the plays because they hope to be made to feel sad, and the feeling of sorrow is what they enjoy. What miserable delirium this is! The more a man is subject to such suffering himself, the more easily he is moved by it in the theatre. Yet where he suffers himself, we call it misery: when he suffers out of sympathy with others, we call it pity. But what sort of pity can we really feel for an imaginary scene on the stage? The audience is not called upon to offer help but only to feel sorrow, and the more they are pained the more they applaud the author. Whether this human agony is based on fact or is simply imaginary, if it is acted so badly that the audience is not moved to sorrow, they leave the theatre in a disgruntled and critical mood; whereas, if they are made to feel pain, they stay to the end watching happily.”