Paul McCartney made an emotional return to his home city and stunned audiences as he toured Liverpool in what fans have called "best Carpool Karaoke ever".

In a 23-minute Youtube video Sir Paul took The Late Late Show host James Corden to visit the people and places that shaped his musical talent, including the home in which he and John Lennon wrote some of The Beatles' biggest hits.

The tour began with a visit to the famous Penny Lane and culminated in an emotional singalong at a city centre pub to the surprise of around 50 punters.

Throughout their journey Sir Paul pointed out notable landmarks from his youth, including a church where he was once in the choir and the barbershop mentioned in Penny Lane.

Corden told him: "Your music is so full of positivity and joy and a message of love and togetherness, I feel like it's more relevant today than it's maybe ever been."

He recounted the story of how he came to write Let It Be, saying a dream of his mother had inspired the song.

Corden labelled it "the most beautiful story" he has ever heard, before the pair perform a version of it.

The Late Late Show host then began to cry and revealed that his grandfather and father once sat him down and played him Let It Be.

From there, they journeyed to the home where Sir Paul lived as a teenager in the Allerton area of Liverpool.

The rocker demonstrated how his music sounded better in the toilet - "the acoustic chamber" - while also showing where he and bandmate John Lennon would write songs.

Sir Paul then took Corden to The Philharmonic pub in Liverpool city centre, where drinkers were treated to a surprise gig.

He played A Hard Day's Night, Love Me Do, Back In The USSR and Hey Jude as members of the audience cried.

Fans couldn't contain their excitement at seeing the performance and many took to Twitter to express their joy, with one user describing it as the "best carpool karaoke ever!!"

Sir Paul's Carpool Karaoke will air in the UK on Sky One at 10pm on Friday.