breaking news
Shia Lebeouf was detained by cops after acting crazy in a New York City club ... law enforcement sources tell TMZ.
Shia was at a cabaret show at the legendary Studio 54 Thursday night ... when he was smoking inside -- which is against the law -- and "alarming people" by his conduct by being extremely loud.
Police came and handcuffed the actor and taken to the cop shop, where's he's being held.
It's unclear if Labouf will be charged with a crime.
