School friends Les Hicks, Graham Palfrey and Teddy Fallon, all 66, had no idea they would meet one of the band on their way to the gig as sixteen year-olds.
Mr Hicks, a retired musician, recalled: "We got on the train at Newport and saw Paul McCartney as we walked along the corridor looking for a seat."
"Paul gave each of us his autograph and wrote the name of his band by his signature and we ended up chatting all the way to Abergavenny.
"He was a really friendly guy.
"I was a drummer in a band and explained we were trying to come up with a name. He suggested 'The Witnesses'- though we never used it.
"When we got to Abergavenny he asked how we were getting into town and said we could share his taxi.
"We jumped in the taxi and drove to the Town Hall."
"The taxi driver looked in his mirror and mistook me for one of The Beatles which was quite funny."
Mr Palfrey, a retired butcher, from Christchurch, said Mr Mccartney had even told a conductor on the train that despite the fact they didn't have first class tickets, they were "with me".
He said the taxi pulled up outside the Town Hall to see girls screaming.
He said: "There were all these girls screaming, it was heaving.
"The hall was throbbing with a crowd of around eight deep on the main floor."
Mr Fallon, a retired engineer of Lliswerry, added: "No one knew they would become as famous as they are but we knew they were good as they had had a number one album 'Please, Please Me' which we all bought."
"Paul went into the theatre via the stage door and we went to the concert.
"We did see him again on the back stairs afterwards."
"It’s lovely that 50 years on the concert is being remembered."
The Beatles, who were supported by local group The Fabulous Fortunes, took to the stage at 10.30pm, after John Lennon flew in by helicopter, and performed in front of 600 fans. Following their performance they attended a civic reception by the mayor and mayoress of Abergavenny, councillor and Mrs Jack Thurston, before spending the night at The Angel Hotel, Cross Street.
As part of the Beatles Weekend, The Cavern Beatles are due to perform at the Borough Theatre tonight at 7.30pm.
Tickets are from the Borough Theatre Box Office or online at www.boroughtheatreabergavenny.co.uk
By Kath Skellon