The late music legend enjoyed a day out in London and was shown around by British singer Tommy Steele, who was considered the British Elvis at the time, it has been claimed.
Theater producer Bill Kenwright, a close friend of Steele's, told BBC Radio 2 that Elvis struck up a friendship with the singer over the phone and they secretly spent a day together in the mid-50s.
Bill said: "Tommy got a phone call one night. The person on the end said, 'They tell me you're good' and Tommy replied, 'Who's this?' The caller said, 'It's Elvis.' Tommy said, 'Get outta here!'"
"They talked and they struck up a friendship. Elvis flew in for the day, and Tommy showed him around London. He showed him the Houses of Parliament and spent the day with him."
Previously it has been thought the closest Elvis, who died in 1977 aged 42, came to English soil was a brief stopover at Scotland's Prestwick airport in 1960.
A spokesperson from Elvis' Graceland estate said: "To the best of our knowledge there was only the one stopover at Scotland."
"We are researching our archives. There are some un-documented areas of Elvis' life."
