This metaphilm essay puts forth an interesting premise:
In the film Fight Club, the real name of the protagonist (Ed Norton’s character) is never revealed. Many believe the reason behind this anonymity is to give “Jack” more of an everyman quality. Do not be deceived. “Jack” is really Calvin from the comic strip Calvin and Hobbes.
It’s true. Norton portrays the grown-up version of Calvin, while Brad Pitt plays his imaginary pal, Hobbes, reincarnated as Tyler Durden.
And Helena Bonham-Carter plays Marla, the grown-up version of Suzie Derkins: