Do you mean like when I was in my early thirties and I had never heard of the book by Stephen King called, "It" since it had not yet been published, I had been having many troubles with real life clowns at the time, even to the point that I could not even sleep in my own bunk (I was traveling with a band at the time and slept in a bunk on a bus) and would prefer to sleep in the walkway than go into my own bunk.
I might awaken with a bitey sharp toothed clown ripping my blankets apart, making direct eye contact with me as it crawled out from between the wall of the bus and the wood and upholstery of my bunk. Slashing the whole way trying to get to me as I kicked and tried to crawl away from it ... and then I would actually awaken, terrified, panting, sweating and most of the rest of the band was also awake wondering WTF was going on.
Few months after some really moving moments, I saw the cover image - the almost exact fucking clown face I had been seeing for moths before.
I generally kept up with Stephen King at that point, but anticipating his upcoming novel, I was not yet ready for at the time.