Dawson Casting: Harry is said to be 35 years old. Alfie Bass was actually 55.
Looping Lines: A great deal of Michael Caine's lines had to be dubbed for the American release due to fears that they wouldn't understand his London accent. He claimed that Shelley Winters couldn't understand him, so she watched his mouth movements.
Pop-Culture Urban Legends: There's an unproven rumour among British jazz enthusiasts that the saxophone solo played on the theme, credited to Sonny Rollins, was actually performed by jazz legend Tubby Haynes.
Referenced by...: A character in the Endeavour episode "Sway" (which is set in 1966, the year Alfie was released) heavily and knowingly models himself on the title character.
Michael: And he (John Wayne) was registering in the Beverly Hills Hotel, and he looked up and he saw me in the corner. And he said to me "What's your name, kid?" I said "Michael Caine". He said "You in that movie Alfie?" I said "Yeah". He said "I saw that." He said "You're gonna be a star, kid." I said, "Oh, thank you sir."
Creator Backlash: Jude Law would go on to say that he was disappointed how his role in this remake turned out, although he added that he doesn't regret doing it and it was one of the best experiences he had working on a film.
Creator Killer: Director Charles Shyer wouldn't make another film for eight years.
Fake American: Although born in New York, Sienna Miller was raised in the UK and thus puts on an American accent to play Nikki.
Romance on the Set: Jude Law and Sienna Miller became engaged shortly after filming, but it ended infamously with infidelity on his part with their children's nanny.