Lorelei Lee is a beautiful showgirl engaged to be married to the wealthy Gus Esmond, much to the disapproval of Gus’ rich father. When Lorelei goes on a cruise accompanied only by her best friend, Dorothy Shaw, Esmond Sr. hires a private detective, to follow her and report any questionable behavior that would disqualify her from the marriage.

Lucy is set up on a date with Dean Martin's movie double Eddie Feldman. When Eddie can't make it because he's needed in a scene, Dean substitutes as him on the date. Throughout the evening, Lucy keeps telling him how much more talented he is than that lucky Dean Martin. To make matters worse, Dean/Eddie can't get a drink anywhere.