He said: “I do smoke; I do everything I’m not supposed to do. Weed is my crutch, my muse, the lesser of all evil. I’ve spent a good £320,000 on pot.”
The 36-year-old crooner – who is married to ‘Precious’ actress Paula Patton – even has a friend get him marijuana, which can legally be prescribed for medicinal purposes in California, to help his “bad knee”.
He is quoted by The Sun newspaper as saying: “My buddy runs a store. I can get medical marijuana when I’m at home. It’s a non-stop chimney.”
Robin has tried to give up his illicit habit but so far to no avail.
He added: “I’ve tried to quit smoking. I’ve quit everything once.”
The singer’s marijuana use has previously got him into trouble with the law, as he was arrested for possession in February 2012 after being caught lighting up in the back of a car in New York City, where the laws on marijuana possession and use are tougher.
A source said at the time: “He wasn’t driving. He was sitting in the car. He was arrested and a small amount of marijuana was recovered on him.”