Up in Smoke, the hilarious cinema debut from Cheech Marin and Tommy Chong, is currently enjoying its 40th anniversary. The comedy duo is not just celebrating the staying power of their stoner classic, but they’re also reflecting on how their comedy helped change people’s attitudes about marijuana.

Up in Smoke cost a paltry $2 million, but made $44 million at the box office. It was still a tough sell, because as producer Lou Adler told LA Weekly, “You’re president of Paramount Studios, I come in off the street and I say I’d like to make a film about marijuana with a Chinese man and a Mexican. Are you jumping out of your seat to make it?”

During the time the film was made, Marin saw marijuana “as the new norm... everybody was doing it even if nobody was talking about it. So we were right out front with it, blatantly, because it’s what we saw everywhere.”

As Marin told Rolling Stone, “We came right up from the streets with an unfiltered view, but it was what was normal to us. We kept saying, ‘We are middle-of-the-road-dopers. We represent the norm. You just don’t realize it yet.’”

Chong told Lohud that he feels Up in Smoke has lasted because “it’s still relevant,” and that it “showed how innocent marijuana really is and how much of a racial excuse it was for the cops and for the establishment. It was just an excuse to harass hippies and black people, and brown people.”

Today, Marin tells Yahoo! Entertainment that Up in Smoke is “totally responsible” for the current movement to legalize pot. “We’re ready for our royalties,” he joked.

On the other hand, Tommy Chong said, “Personally think it would've happened sooner had we not made the movies. They kept looking at us and saying, 'We can't legalize this stuff. Look at these guys!'”

With 29 states legalizing medical and/or marijuana for adult use, Marin says, “We’ve passed the tipping point. The boulder’s rolling downhill now.”

Chong added that noted marijuana opponent, U.S. Attorney General Jeff Sessions, is “the best reason in the world why it should be legal.”

As far as the medical benefits of marijuana, Marin admits he was “always really dubious about [that], until I started getting nausea. I started treating it with marijuana, it instantly took it away, more than any other prescription medication I was getting. I’m a believer.”