Sir Paul McCartney has admitted that The Beatles took too many drugs throughout their career.

He told Entertainment Tonight: "We were overdoing substances and really getting crazy, as we all were.

"We'd be falling asleep, the kinda thing when you can hardly get your head off the pillow. You go, 'Woah, I'd better get my head off this pillow.'"

However, Macca also revealed that his dabbling with drugs had inspired him to write on of his most well-known hits.

He said: "I had a dream, where my mother, who had been dead, by then, 10 years came to me in the dream and was very sort of helpful and very calming, and it was lovely just to see her... and she said, 'Don't worry about it... Let it be'.

"'I went, 'OK', and I felt so good... and I woke up and wrote Let It Be. I thought, 'That's a good idea for a song.'"