EXCLUSIVE

"American Horror Story: Freak Show" star Ben Woolf is in critical condition after he was struck in the head by a moving car in Hollywood Thursday night ... TMZ has learned.

Law enforcement sources tell us ... the 4'4" actor -- who plays Meep and was heavily featured in the current season of the show -- was struck in the head by the mirror of a passing SUV as he crossed a Hollywood street. He was rushed to a nearby hospital.

Cops say they did not ticket the driver because Ben was jaywalking when he was struck.

As for Ben ... he remains in intensive care.