He said: "I have thought about this a lot and I am going to have a conversation with them probably earlier than you would want to have a conversation with children about drugs.

"Then it is up to them if any of them fall by the wayside. But I hope to terrify them before they even consider it."

The 46-year-old pop star spoke of his belief that drugs let "dark energies" into the body.

Speaking Instagram Live, he said: "I think drugs are sort of like a chemical ouija board.

"I am sure we have all been interested in what the ouija does and getting scared and all that business. I think drugs is the same as ouija board.

"I think they let in very, very dark energies that come in and consume you."

And Robbie - who lives in Los Angeles with his family - criticised the drinking culture in the UK and branded people "deluded" for not recognising the problems of drugs and alcohol.

He said: "The thing about drugs and drink is the delusion. In the UK and many places, it's as natural as breathing.

"You just do not think about it -- you leave school then you go to the pub and that is it, and then you drink.

"What I am finding since I have actually been properly sober is what a delusion that way of thinking is.

"We don't need any of that stuff. Then it becomes a crutch and then people rely on it and I totally get it.

"But it's such a crying shame that it is such a natural thing to do. I think it shouldn't be a ­natural thing to do."