Russell Brand has said "love and compassion" and abstinence-based recovery are the key to weaning addicts off drugs.
The actor and comedian spoke before a parliamentary committee about his own experience of addiction, and said society should not "discard people, write them off on methadone and leave them on the sidelines".
During a 30-minute appearance, the Arthur star told the Home Affairs select committee he believed drugs should be decriminalised, with addiction treated as a potentially fatal illness instead.
He said: "I'm not a legal expert. I'm saying that, to a drug addict, the legal aspect is irrelevant. If you need to get drugs, you will.
"The criminal and legal status, I think, sends the wrong message. Being arrested isn't a lesson, it's just an administrative blip."
Brand, who wore a black hat, gold chains and crosses and a torn black vest top to the hearing, said abstinence-based recovery for addicts would help "neutralise the toxic social threat they pose as criminals".
The star, who said he had beaten a heroin addiction which saw him arrested a dozen times, was giving evidence to MPs reviewing the Government's drugs strategy.
Brand said he was not calling for "a free-for-all where everyone goes around taking drugs". Instead, he said addiction should be treated as an illness and society should recognise that addicts, with the proper help, can become active and useful members.
Asked about the role of celebrities, he said: "Who cares about b****y celebrities?"
During the lively and energetic 30-minute hearing, Brand also addressed MPs as "mate" and, when pushed for time by chairman Keith Vaz, replied: "Time is infinite. We can't run out of time. Who's next? Theresa May? She may not turn up. Ask her if she knows what day it is."