An honorary membership of the Beatles Fan Club presented to a four-year-old boy by the pop legends is expected to fetch thousands of pounds at auction this weekend.
Beatles-mad toddler Russell Jamieson came to the attention of the Fab Four after running away from home to join the band in the summer of 1963.
The young fan even gave his name as Russell Beatle when he was found by a police officer wandering the streets of Liverpool.
Russell, from nearby Kirkby, was safely returned home but the story of his escapade reached the attention of John, Paul, George and Ringo, who had fan club secretary Anne Collingham send him an honorary membership of the organisation.
The autographed card is thought to be the only honorary membership ever awarded by the fan club and was addressed "To Russell - our youngest Fan Club member".
It comes with a letter from Ms Collingham which said: "At the special request of John, George, Paul and Ringo I have much pleasure in inviting you to become an honorary member of the Official Beatles Fan Club.
"I am enclosing your membership card and a couple of special photographs which I am sure you will want to add to your collection."
Mr Jamieson, who is now 53 and lives near Oslo, Norway, said:
He said that after he was taken home by the police there was a story in the Liverpool Daily Post newspaper which was seen by the band and a few weeks later the letter from Ms Collingham arrived.
His memorabilia is expected to fetch up to £7,500.
He said: "I am thrilled there is so much interest in my collection of memorabilia.
"They were magical and wonderful days which I will never forget."
The annual sale, part of the Beatles Convention in Liverpool this weekend, is attracting huge levels of interest, the organisers said.
It was 50 years ago this week that Ringo replaced Pete Best as the drummer and the final Fab Four line-up was complete.
Stephen Bailey, manager of the Liverpool Beatles Shop, which is staging the auction, said: "We don't know of any other honorary members of the Official Fan Club so it's a remarkable story and there's bound to be great interest in the auction of the membership card."
Other lots in the auction include a rare ticket for the Beatles' last performance at the Cavern Club - on Saturday, August 3 1963.
The ticket, which originally cost 9/6, is expected to fetch around £7,000.
There are a total of 322 lots being sold in the auction, which will take place this Saturday, August 25, in the Paul McCartney Auditorium at Liverpool Institute for the Performing Arts. For more information visit www.beatlesauction.co.uk.