Literally, the last time we had seen him was 'Billy Elliot,' and you don't necessarily think of that kid to play a senior in high school, ... But we were really lucky. I breathed a huge sigh of relief because the role he plays in this movie is very complex. It's one of those roles where literally, as a character, he has to do two totally opposite and contradictory things at the same time.

Lou was absolutely fearless. He's this charming, polite young man - until you turn the camera on. Then he dives out there without a net. And when he's onscreen, he draws your eye. It's a magnetic thing.

We weren't writing it to sell the film and weren't writing it to sell the movie; we were literally going to make it ourselves, ... So, we were picturing Ralph Fiennes from the very beginning, but more in a way of, 'You know who would be great for this role? Ralph Fiennes,' not even thinking he'd ever do it.

We had this drug dealer, but instead of him selling street drugs, we said, 'Let's have him selling prescription drugs,' ... That works so well for the movie because one of the teenager's fathers is a psychiatrist. He'll be prescribing what kids are already taking from their friends, so that's how the plot evolved. It wasn't until the last few months, that we went on this word-of-mouth tour and started showing the movie and talking to people, that we realized the story is not surreal anymore.

Lou was absolutely fearless, ... He's this charming, polite young man - until you turn the camera on. Then he dives out there without a net. And when he's onscreen, he draws your eye. It's a magnetic thing.

Billy Wilder used to say, 'The best movies have a tiny bitter pill that you want the audience to swallow, but to get to the swallow, you coat it in lots and lots of sugar,'