Christopher Nolan fears films could disappear if they are only available via streaming services.

The Hollywood director has admitted he wants to keep physical media like Blu-ray going because he worries that expiring licensing agreements with platforms like Netflix or Apple could lead to some movies getting lost over the years as they disappear from online viewing platforms and become unavailable.

Nolan recently urged film fans to buy physical copies of his latest film 'Oppenheimer' during a screening of the film, telling them they need a physical copy so "so no evil streaming service can come steal it from you" and he has now explained the comments to The Washington Post.

He told the newspaper: "There is a danger these days that if things only exist in the streaming version, they do get taken down. They come and go - as do broadcast versions of films, so my films will play on HBO or whatever, they’ll come and go.

"But the home video version is the thing that can always be there, so people can always access it. And since the 1980s, as filmmakers, we’ve taken that for granted, and now we have to make sure that there’s a way that that can continue to happen, if not the physical media."

He added: "The danger I’m talking about with a filmmaker’s film just sort of disappearing from streaming one day and then maybe not coming back or not coming back for a long period of time, that’s not an intentional conspiracy.

"That’s just a way that with the particular licensing agreements, the way things are evolving. So it’s something worth pointing out because it will need to be fixed, but I’m very confident that it will be."

Speaking during a screening of 'Oppenheimer' in Los Angeles last week, Nolan told the audience he's been working hard to get the film released on physical media. He said: "Obviously 'Oppenheimer' has been quite a ride for us and now it is time for me to release a home version of the film. I’ve been working very hard on it for months. I’m known for my love of theatrical and put my whole life into that, but, the truth is, the way the film goes out at home is equally important.

"[The Blu-ray is] a version you can buy and own at home and put on a shelf so no evil streaming service can come steal it from you."

'Oppenheimer' will be released on Blu-ray on November 21. A date for the film's launch on streaming services has yet to be announced.