Prince Harry took cocaine at the age of 17.
The 38-year-old prince has recalled that he was offered a line of cocaine during a hunting weekend - but he didn't find it to be "much fun".
In a translation of his memoir 'Spare' - which has been obtained by MailOnline - Harry writes: "It wasn't much fun, and it didn't make me feel particularly happy the way the others seemed to, but it did make me feel different, and that was my main goal. To feel. To be different."
Harry admitted that at the time, he was a 17-year-old "willing to try almost anything that would upset the established order".
The prince also confessed to smoking cigarettes and cannabis while he was a student at Eton.
In 2005, Harry was widely criticised after he was photographed wearing a Nazi costume to a private party.
The prince recently described the incident as "one of the biggest mistakes" of his life.
He shared: "It was probably one of the biggest mistakes of my life. I felt so ashamed afterwards. All I wanted to do was make it right."
Harry - who has Archie, three, and Lilibet, 19 months, with the Duchess of Sussex - was determined to learn from his mistake.
And he subsequently made a concerted effort to educate himself about Nazi atrocities.
In his 'Harry and Meghan' documentary series, he explained: "I sat down and spoke to the chief rabbi in London, which had a profound impact on me. I went to Berlin and spoke to a holocaust survivor.
"I could have just ignored it and got on and probably made the same mistakes over and over again in my life, but I learnt from that."