New dad Joseph Gordon-Levitt can’t understand why there is such a stigma attached to marijuana use, because the drug has helped make him a better actor.

The Inception star has always been open about smoking weed, which is still illegal in most states, especially because it helps many people much more than it hurts them.

He tells Playboy magazine, "Even though the tide is turning, I think marijuana is overly demonised in our culture. I do know people who let it get out of control and let it play a part in their lives that’s not beneficial. There’s definitely an addictive quality, but it’s psychological. It’s not physically addictive in the way cigarettes or alcohol are physically addictive."

And Gordon-Levitt, 34, claims cannabis has played a major role in his career to date - because it has improved his creativity.

He adds, "When I smoke weed I'm more liable to make connections I wouldn't otherwise make. Sometimes those connections are ludicrous, but sometimes they're great. You’re like, 'Oh s**t, I might not have thought of that', and it actually makes sense in the morning."

The actor never smokes while he is making movies, explaining insurance concerns make drug-use illegal on set, but he has shared a joint with fellow industry stars - while he was making upcoming biopic Snowden, he lit up with director Oliver Stone on several occasions.

He recalls, "With Oliver it was really nice because most of the time we were in this kind of high-stakes situation of working, and when we were smoking, we just smoked and watched a couple of movies a few times."