The photos were taken of the band in 1961 and show the original line-up of Paul McCartney, John Lennon, George Harrison, and drummer at the time, Pete Best. Best was replaced by Ringo Starr a year later.
The images were apparently taken when the band were just back from a gruelling tour in Germany, where they had played 500 hours on stage within 90 days, according to historian Mark Lewisohn, who’s written several books on the band.
The historian described the band, who in the pictures are aged between 18 and 20, as “whippet-thin under-nourished lads”.
He added: “So slender has this marathon made them, it’s as if their heads and bodies are stranger.
“A look emphasised by the unusual clothes - leather trousers and cotton tops. No other photos show them dressed this way.”
According to Lewisohn, the photos show the band playing to a lunchtime or evening audience in June 1961 – just over one year before they released their debut record “Love Me Do” in October 1962.
The photos show the band pre ‘Beatle Haircut’ – the iconic look they became known for – which they got in Paris a few months after the images were taken.
"Days later, Brian Epstein saw The Beatles in the Cavern, offered to become their manager, and set them on a course that changed our world,” Lewisohn added.