She explained: "Sometimes I got onto him and said, "I don't want to hear that song again".
The guys then ended up at a pub where Paul surprised the locals by performing several songs for an emotional crowd.
McCartney recalled how he "had a dream in the '60s where my mum, who died, came to me in the dream and was reassuring me, saying, 'it's going to be OK".
Corden labelled it "the most handsome story" he has ever heard, before the pair perform a version of it.
With 1 billion users, Instagram takes on YouTube in video
The user update shows Instagram moving further ahead of Snapchat, which lags behind with around 100 million monthly active users . But Instagram isn't yet doing one thing that YouTube started doing early on: cutting creators in on ad profits.
Paul McCartney joins James Corden on very memorable episode of Carpool Karaoke.
They visited the house that McCartney lived in from, he says, the ages of about 12 or 13 to 18 or 20, where Corden and McCartney did a rendition of "When I'm 64" with the current resident joining in. They also stopped by the barber shop mentioned in "Penny Lane" and mingled with excited fans along the sidewalks. "Couldn't you sing She loves you, yes, yes, yes?'" "If my granddad was here right now, he'd get an absolute kick out of this", Corden said.
Carpool Karaoke was clearly Corden's breakout, but I like how he's used the segment not as a senseless gag to boost YouTube views, but as a real opportunity to get to know the guests that ride around in the auto.
Even Corden himself agreed that it was his favourite edition of the show to date.
The singer revealed that the band thought their music would only last 10 years and expressed his shock at its continued endurance.