We like Alan Cumming’s explanation best, in re Shia LaBeouf’s behavior at a performance of Cabaret over the summer. Cumming gave his version of the encounter to Conan O’Brien last night on Conan’s TBS show, as he made the late night rounds to promote his new book, “Not My Father’s Son”.

“Well, he was really messed up… He was just wasted, and he was wasted from the second he walked in,” Cumming said.

“There was an atmosphere – when I went down to go onstage and start the show, everyone was freaking out, because there was, you know, someone who seemed to be a crazy person,” Cumming began.

LaBeouf, who has said his behavior that night was performance art , last month pleaded guilty in Manhattan criminal court to charges stemming from his disruption of the performance of Cabaret at Studio 54. The plea bargain deal included no lockup or probation. Police said LaBeouf disrupted the performance with his smoking, yelling at actors, cussing at security personnel — and, according to Cumming, slapping of the actor.