Woody Harrelson is quite famously, shall we say, fried. Even his recent Saturday Night Live monologue was all about his inability to remember the entire year of 1989, because of, you know, "the drugs," as he put it.
But it's still a little surprising in this interview for Catching Fire that even after having made two massive films with Liam Hemsworth, he had no idea that the other massively famous Hemsworth, Chris Hemsworth, was his brother.
Have to say, we like Woody even more for it. His reaction is in the video when he realizes it is so real, and probably strong evidence that Woody is respectably outside of the Hollywood "scene."