Cate Blanchett wore a sock down her trousers to play Bob Dylan. The actress said it "helped me walk like a man."
Colin Farrell was originally cast as Robbie Clark. He dropped out of the film to admit himself into rehab for a dependency on back pain medication. Heath Ledger replaced him. Farrell would later take over for Ledger in The Imaginarium of Doctor Parnassus (2009) after Ledger's death.