Paul McCartney spoke candidly about his mid-1960's drug use, his belief in a higher power, and his late wife Linda McCartney, who died 20 years ago. During a chat with Britain's Sunday Times Magazine McCartney recalled his initial trip after taking the incredibly potent hallucinogen DMT (Dimethyltryptamine), with his good friend, the late art dealer Robert Frasier. McCartney remembered, "We were immediately nailed to the sofa. And I saw God, this amazing towering thing, and I was humbled. It was huge. A massive wall that I couldn't see the top of, and I was at the bottom. And anybody else would say it's just the drug, the hallucination, but both Robert and I were, like, 'Did you see that?' We felt we had seen a higher thing. I can just see the bloody headlines now: 'I saw God!' And what I’m saying is, that moment didn’t turn my life around, but it was a clue."

He went on to explain that that moment fed into a type of spirituality that he's carried with him throughout his life: "Having lost both my parents and Linda, and having experienced people close to me dying, you often hear this from others when you say you're missing a person so much. 'Don't worry,' they say. 'They're here, looking down on you.' And there's part of you that thinks there is no proof of that. But there's part of you that wants to believe it. I like to allow myself to think that happens, rather than stopping myself thinking of the possibility."

McCartney spoke about an instance where he felt as though he received a sign from above: "I was in the country once, and I saw a white squirrel. So, this was Linda, come back to give me a sign. It was a great moment. It thrilled me. Goosebumps! Obviously, I have no proof it was her at all, but it was good for me to think that."

He went on to say, that he's just as unsure about life as the next guy: "Did you think, when you were a kid, that at some point you would have it all down. That you would have sussed the whole thing out and wouldn't have to think about new challenges? Well, I don't find that to have been true. Life isn't like that. It keeps throwing you a curveball. It keeps moving. It keeps it intriguing. Also, if you have children, you always learn lessons, because there's no accepted way to bring them up. It's the biggest ad-lib of your life, as they tell you one thing, but your kid might not fit that mold. Throughout history, I can't think of anyone who didn't have some kind of insecurity."

Although in 1967 Paul McCartney was the first Beatle to announce to the press he had taken LSD, he in fact was the last to take it, having waited nearly two years after John Lennon and George Harrison were spiked with the drug by their dentist at a dinner party: "I really was frightened of that kind of stuff, 'cause it's what you're taught when you're young; 'Ay, watch out for them devil drugs!' So when acid came 'round, we'd heard that you're never the same. It alters your life and you never think the same again. And I think John (Lennon) was excited by that prospect, I was rather (laughs) frightened by that prospect -- 'Uh, just what I need?' So I delayed and I was seen to sort of stall a little bit within the group, 'cause there was a lot of peer pressure. I mean talk about peer pressure -- The Beatles?"

AUDIO: PAUL MCCARTNEY ON DRUGS