Sir Paul McCartney and James Corden. Picture: Bang Showbiz

Sir Paul McCartney admitted on 'Carpool Karaoke' that he only expected The Beatles' success to last for 10 years.

The 76-year-old musician admitted he never expected his legendary group's music to still prove popular and relevant today.

During a segment of 'Carpool Karaoke' on 'The Late Late Show, host James Corden commented about their music: "It touches on positivity, joy, love and togetherness, which I think is more relevant today than ever!"

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Paul replied: "We expected it to last for only 10 years."

The Wings star - who showed his co-passenger the sights of his home city of Liverpool, North West England, including his childhood home and a barbershop on Penny Lane - also spoke movingly about his late mother, who passed away when Paul was just 14, visiting him in a dream, with the vision resulting in him penning 'Let It Be'.

He said: "I had a dream in the 60s about my mum, who died when I was young. She came to me and reassured me, saying 'It's going to be OK, just let it be.'

"I felt so great, she gave me such positive words. She said 'Let it be', so I wrote the song!"

The host replied: "That's the most beautiful story I've ever heard."

The pair then sang along to the track, but James, 39, broke down in tears afterwards because of the memories it evoked.

He wiped his eyes as he said: "I remember my grandad and dad playing this song to me, and said, 'This is the best song you'll ever hear.' 

"If my granddad was here, he would get an absolute kick out of this."

The iconic musician replied: "He is."

The segment ended with Paul delighting around 50 drinkers at the Philharmonic pub with a set of his biggest hits and two previously-unheard tracks, ending with James joining him for a rendition of 'Hey Jude' - and again struggling to keep back the tears.