People have been left scratching their heads after spotting an unusual sighting in a video recorded at an Elvis Presley concert in 1977 - and conspiracy theorists are convinced it proves time travel.

Nearly 3,000 fans from around the world braved the cold and gathered at Graceland to mark what would have been Elvis Presley’s 90th birthday.

circa 1957: American singer and actor Elvis Presley (1935-1977) performing outdoors on a small stage to the adulation of a young crowd. (Photo by Hulton Archive/Getty Images) Elvis Presley is one ...

"So I call up my wife, and I’d say, ‘Baby, who can draw crowds like me.' Nobody, nobody can. I’m the greatest of all time, ...

About 25 Elvis impersonators, from Florida to New England, are expected to shake their hips and croon to the crowds to compete for a cash prize and the chance to move onto the “King of the World ...

Elvis Presley kicked off a seven-year residency at the then-new International Hotel in 1969, belting out hits in front of more than 600 sold-out crowds. In the years since, impersonators in iconic ...