Although Robert Downey Jr.'s days of drugs and frequent arrests are behind him, it turns out Japan isn't too forgiving of those old felony convictions, Huffington Post reports.

Downey told David Letterman about his troubles at a Japanese airport last year, where he was detained and interrogated while promoting 'Iron Man.' "I think it has something to do with my fairly distant past," he said. "Not recent stuff like you or Tiger." Watch the video below.