The British rocker's bereavement will always be close to the surface, as he will never be allowed to forget the untimely deaths of his songwriting partner Lennon, who was shot in 1980, and Harrison, who passed away after a battle with cancer in 2001.
He says, "We can't last forever and one of us has got to go first, and another one's got to go second. Now it's very sad, just me and RINGO (STARR) left.
"It particularly hits me when I'm asked to sign a picture, and it's always the four of us.
"Suddenly there's a little jolt, 'cos I just see two of the guys there: John and George. Oh. F**k. It's just sad. Like any bereavement."