Throw It In: The scene where Isabelle's hair catches fire happened unplanned. Eva Green was supposed to lean forward and kiss Matthew goodnight but accidentally caught her hair on fire on the candle on the table. She didn't let it worry her and acted so natural that Bernardo Bertolucci decided to leave it in as he felt it demonstrated perfectly the cross over in the film that things are about to get a bit crazy!
What Could Have Been: There were scenes in the script depicting much more blatant sexual relations between the characters of Matthew and Theo, but they were not filmed. Director Bertolucci said, "The gay sex was in the first script, but I had a feeling that it was just too much stuff. It became redundant." Actor Pitt said in interview, "It was in the script and it's what I'd signed to do. But they said we weren't going to do that."