Sir Paul McCartney is relieved he and John Lennon were able to reconcile their differences.

The Fab Four - which also featured Ringo Starr and George Harrison - formed in Liverpool in 1960, but after enjoying incredible success throughout the world, they split in 1970 because of internal troubles.

However, Sir Paul says he's glad that he and John were able to patch up their differences before his death in 1980 at the age of 40.

Sir Paul shared: ''There was a big business thing and everything got very sour and then that kind of just got boring and I would just ring John and eventually it just got friendly again ... So now he had a baby and I was bringing up babies so we could talk about that.

''You could talk about normal stuff so it got very nice and I said, to this day, I'm so glad because it would have been the worst thing in the world to have this great relationship that then soured and he gets killed, so there was some solace in the fact that we got back together.

''We were good friends.''

Sir Paul also admitted he struggles to comprehend the actions of his killer, Mark David Chapman, who shot John in the back four times.

He told 'The Jonathan Ross Show': ''For me it was just so sad that I wasn't going to see him again and we weren't going to hang out and for me the biggest thing was that the guy who has took his life... The phrase kept coming in my head 'The jerk of all jerks'.

''It was just like 'this is just a jerk, this is not even a guy politically motivated, it's just some total random thing.'''