Andrew Garfield took hallucinogenic mushrooms to find his "true self".
The 'Hacksaw Ridge' actor wanted to go "to the depths" and beyond the "hell of being a human" to find answers within himself.
He explained: He said: "[It was about] going to the depths, past what you call the first layer, which is 'Everything's great!', to the second -- the hell of being a human. Inadequacies. Jealousies. Terror. Fear. Paranoia. Self-loathing. The s**t.
"What's underneath, the third layer, is the true self, and I'm interested in that, in what Cat Stevens talked about when he said, 'The answer lies within, [so] why not take a look?' "
Andrew also admitted he is "excited" about having children.
The 34-year-old actor - who has been single since splitting from Emma Stone two years ago - is looking forward to starting a family one day, but worries about the state of the world he'd be raising his kids in.
Asked about having children, he said: "[I am] excited about the idea [but I] can't help but be aware of the world I would be bringing a human into... Obviously that's ridiculous."
The 'Breathe' actor admitted he worries about the culture of fame, and blames the worship of people in the spotlight for America ending up with an "idiot celebrity" - former 'Apprentice' star Donald Trump - as president.
He told the Sunday Times Culture magazine: "Look who's in the White House. It's an idiot celebrity, and we enabled that.
"It's not just the people who voted for him, it's the whole culture.
"We started worshipping things that are empty and false, and, you know, here we are.
"It's not sneery. I have total understanding, but I wish we could wake up to the fact we're being brainwashed."