Peter O'Toole was originally cast as Toby Dammit. After he pulled out, Federico Fellini contacted a London casting agency and asked them to send the most decadent actors they had to Rome to see him. They sent Terence Stamp and James Fox, and Fellini chose Stamp.
Fellini had spent most of 1967 working on the " Yoyage of G. Mastorna" with Marcello Mastroianni and Dino de Laurentiis but it collapsed due to health and personal problems suffered by the director. This was his first work since " Juliet of the Spirits" in 1965.