Determining which song was Elvis' biggest hit is a tricky thing, as he has enjoyed one of the longest and most successful ...

It was a single that I remember ... It's Now Or Never had been the biggest international hit of Elvis Presley's career, eventually selling an astonishing 25 million copies worldwide.

Determining which song was Elvis’ biggest hit is a tricky ... Now Or Never” — which is believed to be Presley’s biggest international hit, selling roughly 25 million copies worldwide.