A day in the life of James Corden often involves cajoling celebrities into his auto as he cruises in Los Angeles, where they enjoy conversation and belt out songs together as part of the "Carpool Karaoke" segment on Corden's Late Late Show.
The two then launched into an emotional rendition of the iconic song as Corden teared up. "She said, 'Let it be.' That's kind of good.' So I wrote the song 'Let It Be, ' but it was her positivity".
McCartney made it even more poignant when he told Corden: "He is".
Their conversation got emotional as McCartney recounted a dream he'd had where his mother reassured him everything was going to be OK.
"I can remember my granddad, who's a musician, and my dad sitting me down and saying, "We're gonna play you the best song that you've ever heard" and I remember them playing me that", Corden explained.
After getting back in the auto, Corden says Sir Paul's music is "so full of positivity and joy", and "more relevant now today than it's maybe ever been". "And it keeps being relevant".
They snapped a selfie in front of a barber shop and then McCartney autographed the Penny Lane wall.
"I've never been in since I lived there", Sir Paul says.
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.
What did you think of this episode of Carpool Karaoke? "We're going to give the locals the surprise of their life", teased Corden.
All the while, the two sing some of the Beatles' biggest hits, such as "When I'm Sixty-Four", "Blackbird", and "A Hard Day's Night", as well as "Come On to Me", one of Paul's two new songs, released just last June 20, from his new album Egypt Station.