The legendary star said his former band consumed a copius amount and he said he was surprised they had managed to survive.

Speaking to Entertainment Tonight, he said: "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."

But he said some drugs had a positive effect, especially on his songwriting.

He added: "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'."