Elvis Presley and Ann-Margret recorded a duet, a Jerry Leiber / Mike Stoller piece called "You're the Boss", but it was never used in the film. It has been released since.
About 15 seconds into Ann-Margret's dance routine at the University of Nevada, the red-haired male dancer third from the left, wearing grey pants, white shoes and black socks, suddenly becomes a different person with blond hair, white pants, grey shoes and white socks.
At the end of the race the counts car runs off the track and then back on wherein the cockpit gets pulverized by a yellow car. This would definitely have killed the driver, or at least put the "count' into a full body cast. Yet later he appears at Rusty and Lucky's wedding, very healthy.
Of course it is!...No other woman who starred with him (and there were many) had quite the star-power Miss Ann had and still has to this day. Elvis was so smitten with her that multiple takes were neccesary for almost every scene! Its been claimed many times that Col. Tom Parker strongly advised "his boy" never be matched with that fiery woman again" in fear he'd always be upstaged each time...