Ann-Margret (Elvis' co-star in 'Viva Las Vegas') was in discussion to play the part of Nellie, as she owed Edward Small a film under her contract with him.

Eileen Wilson's voice was dubbed for Donna Douglas' singing scenes. It is her voice on the soundtrack as well.

For the soundtrack, this was the first time that the instrumental tracks were pre-recorded and then Elvis came in the following day to do vocals, rather than doing everything at once. The official rationale was that this was a more efficient, modern method of operation, but according to Alan Fortas the real reason was because Elvis threw a temper tantrum in the studio the first night because of his distaste for the music.

Several retakes were required because Elvis' form fitting slacks were judged to be too revealing, but the cost of re-filming crowd scenes was considered to be too expensive, and so Elvis and his bulge were occasionally left intact.

The steamboat seen during the opening credits was the Delta Queen, and was actually filmed and used in the 1957 Elizabeth Taylor movie, 'Raintree County'. Which was filmed south of Cincinnati, around Anderson's Ferry. Other steamboat scenes include studio stock footage of California steamboats and the steamboat that was used in the MGM production of 'Showboat.' Some sources claim that the SS Mississippi Queen was used in the movie, but it wasn't built until more than 6 years after the movie's release.

Continuity

When Blackie puts the live round in the stage gun, it's a Colt single action. After Frankie shoots Johnny, the pistol is now a Colt double-action revolver that wasn't even introduced until years after the movie was supposed to be set.



Factual errors

While singing the song "Hard Luck", Johnny walks passed the large front windows of a general store. Several modern carbon-steel shovels are seen inside the window display, each prominently labeled with a large modern printed glued label by their manufacturer. This rather blatantly shows they were simply purchased from a store, and not true to the design and style of shovels made during the setting of the film.

Johnny's talisman could not stop a bullet fired at point-blank range.



Audio/visual unsynchronized

When Johnny pulls down Cully's beard during the Mardi Gras party, Cully says something as he fixes his beard, but his lips never move.