Sir Paul McCartney has explained how The Beatles hit 'Help' was really a "cry for help" from John Lennon.

Sir Paul McCartney

Sir Paul McCartney

The Fab Four legend admits his late bandmate - who was shot dead outside the Dakota apartment building in New York City in December 1980 - was "always" looking for help throughout his life and the upbeat track had a deeper lyrical meaning for Lennon.

Lennon gave a famous quote in a Playboy magazine interview about his state of mind when he wrote the song in 1965 - a year in which the pressure of touring took its toll and he began experimenting with drugs - in which he said: "When 'Help' came out in 65, I was actually crying out for help ... I was fat and depressed and I was crying out for help."

Explaining Lennon's state of mind, McCartney told Billboard: "(In the song) he didn't say, 'I'm now fat and I'm feeling miserable.' He said, 'When I was younger, so much younger than today.' In other words, he blustered his way through.

"We all felt the same way. But looking back on it, John was always looking for help. He had (a paranoia) that people died when he was around. His father left home when John was three, the uncle he lived with died later, then his mother died. I think John's whole life was a cry for help."

The 'Band On The Run' hitmaker remembers making the 1965 track with bandmates - the late George Harrison, Ringo Starr and John - and how quickly it came together.

He recalled: "I turned up at John's house for a writing session and saw the opportunity to add a descant (a melody in the second verse). We finished it quite quickly; we went downstairs and sang it to John's wife at the time, Cynthia, and a journalist he was friendly with called Maureen Cleave. We were very pleased with ourselves."