It was the meeting of two of the greatest rock'n'roll acts of the 20th century but the first, and only, rendezvous between the Beatles and Elvis Presley almost fell flat, according to a new exhibition in Liverpool.

Elvis and Us, which opens to the public at the Beatles Story museum in Liverpool on Wednesday, has been co-curated with archivists from Presley's Graceland mansion in Memphis, Tennessee.

The show tells the story of the band's meeting with Presley at his house in Bel Air, California, when the group were on their 1965 US summer tour.

It did not start well, according to Tony Barrow, the Beatles' press officer in the 1960s. Having walked past Bentleys and Harley Davidson motorcycles into Presley's home, John Lennon got straight to the point.

"John asked what had happened to the old rock'n'roll Elvis, who at that point was mainly singing the soundtracks to his films," Barrow said. "He was half-joking but he meant it."

Presley laughed off the comment, but the conversation remained stilted until Presley ordered guitars to be brought into the room. "They all started jamming and that is when the party took off," Barrow said. "With words, they didn't have much to say. But as soon as they got into the music the conversation began to spark."

The supergroup made their way through rock'n'roll classics, as well as some Beatles and Presley hits, but drummer Ringo Starr soon felt left out, said Barrow, who features in video interviews in the exhibition.

"Ringo was tapping out a backbeat on chairs, but he soon wandered out of the jam session and started playing pool with some roadies."

The Beatles knew their stay was over when Colonel Parker, Presley's manager, entered with doggie bags – featuring pressings of Presley hits – for everyone there.

Although they were later pleased they had met a star so vital to their own sound, the group members were initially underwhelmed, Barrow said.

"John said it had been about as exciting as meeting Engelbert Humperdinck. Someone else wondered if Elvis was stoned out of his mind, and George Harrison just said: 'Aren't we all?'"

The exhibition, which features Elvis artefacts never before seen outside of Graceland – such as his Las Vegas rhinestone-encrusted jumpsuits and the shirt he wore in Jailhouse Rock – will nonetheless explore the influence he had on the Beatles.

"When the Beatles first went to the states, it was like they were going to the Holy Land, and Elvis was their greatest idol," Barrow said.

"But I don't think it worked the other way – if anyone had anything to fear from the Beatles, it was Elvis."