He says it's a "great source of joy" the pair reconnected before Lennon's death.
Paul McCartney says it's still emotional listening to a song he wrote for John Lennon 51 years on.
The 79-year old has explained the track 'Dear Friend' was him talking to his bandmate after "all sorts of disputes" about The Beatles breaking up.
He says it's a "great source of joy" the pair reconnected before Lennon's death.