Russell Brand took drugs because he felt "lonely".
The British comedian admits he thought heroin was "beautiful" when he first tried it and says he turned to illegal substances because he "couldn't cope" with life.
Russell - who has been sober since 2003 - said: "When I took drugs I felt lonely, alienated and disconnected. I felt that this culture isn't serving me. When I took heroin for the first time it was beautiful. It was a personal problem - I couldn't cope with being alive, I needed to take drugs."
The 38-year-old star - who was previously married to Katy Perry - admits being sober has been good for his whole family.
Speaking about his struggle to stay clean, he said: "My mother's life is better now."
The 'Arthur' star was speaking at elite Cambridge University's union last night (13.01.14) and urged the students - who he jokingly called "Harry Potter p**fs” - to be "spiritual" and not worry about possessions.
He told them: "Don't be materialistic; it doesn't help, just develop spiritually. I try to find union with everything."
And though he is keen for a "revolution" to take place, Russell thinks it needs to be peaceful.
He said: Revolution is coming. It's happening instantaneously. It's happening now! It has to be peaceful - occasionally I get into all that violent s**t and the romanticisation of revolution because I hate the power structure but that just wouldn't work."
And he urged the students to use their education for the good of society.
He said: "Give us something to vote for then we will vote for it.
"Give us a system that is truly representative.
"Use this education that you are receiving to bring about ideas that can benefit not just you but all of us."