Elvis Presley made this film in a deal with floundering Allied Artists, in which he took a pay cut and did not record any new material in exchange for 50% of the film's profits. The film was a big earner, costing $1.5 million and grossing about $5 million worlwide. It was credited with saving Allied Artists from bankruptcy.
In an obvious wink and nod moment during the film, Elvis holds up a letter and says....What do you think this is, a ham sandwich and points at the letter and says Return To Sender. This is obviously referring to his 1962 hit single.
While filming Elvis Presley gave his Sony video camera to director Norman Taurog. At the time those cameras were really rare in the US. Taurog liked the idea of it because with a video camera he could shoot the scene himself and review it before it goes to edit.