The actor reportedly entered Alcoholics Anonymous in 2008 after his arrest for refusing to leave a Chicago drug store. He later admitted he can't handle drinking in moderation.
Speaking to Page Six, LaBeouf disclosed he tried moonshine to prepare for the prohibition film.
"My drinking on this movie was as undestructive as I could possibly make it, if that makes sense," he said. "I did it for the movie. I didn't drink off set for no reason.
"I did it because, when I showed up on set the next day, my [bleep]ing eyes looked [bad] and my face... had that drunk bloat that I needed, that I couldn't have if that wasn't going on... Moonshine is different than liquor. Moonshine is closer to heroin."
LaBeouf also disclosed that his occasionally "aggressive" behaviour frightened his co-star Mia Wasikowska.
"Mia was ready to walk away from the movie," he declared. "I was really pretty aggressive about [staying in character], and not in any kind of weird, strange way, but I don't think she had ever experienced anything like that."
LaBeouf added that he and Wasikowska were ultimately able to become friends.
Lawless will be released on August 29 in the US and September 7 in the UK. Watch a trailer below: