Christopher Nolan says Tenet is his most ambitious movie

Christopher Nolan's new movie 'Tenet' is the most ambitious of his career.

The acclaimed movie-maker is busily working on the upcoming action thriller - which will star the likes of John David Washington, Robert Pattinson, Aaron Taylor-Johnson and Clemence Poesy - and he's now teased details of the new project.

Speaking to Entertainment Weekly, the 49-year-old director - whose previous credits include 'Dunkirk' and 'Inception' - explained: "We're jumping off from the point of view of an espionage film, but we're going to a number of different places.

"We're crossing a few different genres in a hopefully exciting and fresh way. [Producer] Emma [Thomas] and I have put together a lot of large-scale productions, but this is certainly the biggest in terms of international reach.

"We shot in seven countries, all over the place, with a massive cast and huge set pieces. There's no question, it's the most ambitious film we've made."

Meanwhile, Robert Pattinson recently said he was "locked in a room" to read the script for the new film before handing it back.

The 'Twilight' star explained that he was "sworn to secrecy" about the upcoming project.

He said: "I got locked in a room to read the script - I don't have it myself, I've been a little wary of doing big movies for years and years, but there's just something about Chris Nolan's stuff.

"He seems like the only director now who can do what is essentially a very personal, independent movie that has huge scale. I read the script and it's unreal."