Thicke, who was arrested last year in New York for marijuana possession, says the habit has cost him as much as $500,000.
"I do smoke. I do everything I'm not supposed to do," he said. "Weed is my crutch, my muse, the lesser of all evil."
"I've spent a good $500,000 on pot. I've tried to quit smoking. I've quit everything once. My buddy runs a store, I can get medical marijuana. When I'm at home, I'm a non-stop chimney."
That's one heck of an expensive high, but the 36-year-old singer can probably afford it: "Blurred Lines" has sat atop the Billboard Hot 100 for nine-straight weeks, and in his best sales week ever, the album of the same name topped the Billboard 200 with 177,000 copies sold.