Robert Pattinson helped inspire Christopher Nolan to helm 'Oppenheimer' - but was too "busy" to star in the film.

The pair teamed up on the 2020 sci-fi flick 'Tenet' and despite the movie having a link to the 2023 war biopic, the 37-year-old actor didn't have enough time in his schedule to take on a role in the latter film.

Speaking in an interview with Tara Hitchcock, Nolan spilled: “Yeah, Rob, off the back of 'Tenet', where we refer to Oppenheimer, and I had wrote a thing about this incredible moment that Oppenheimer and the scientist of the Manhattan Project had where they could not completely eliminate the possibility that when they triggered that first gadget, that first atomic device, they might start the chain reaction that would destroy the world."

However, a special gift he gave the director got him "hooked" on the story of 'Oppenheimer'.

Nolan, 52, continued: “We used that as a metaphor for Tenet, which Rob was in. As a wrap gift, he gave me a book of Oppenheimer‘s speeches from the 1950s, where you’re reading these great intellects trying to deal with the massive consequences of the way in which they’ve changed life forever, for all of us."

He said: “I really got hooked and got hooked on the story."

The filmmaker added that Pattinson was too "busy” to take on a role in the flick as he's "very much in demand these days.”

The motion picture is about J. Robert Oppenheimer, the creator of the atomic bomb, and has an all-star cast featuring Cillian Murphy, Robert Downey Jr. and Florence Pugh.

Nolan recently confessed that he was "relieved" to have completed the movie as it had left him emotionally drained.

He explained in an interview with Wired magazine: "I was relieved to be finished with it, actually.

"But I enjoy watching the film tremendously. I think you'll understand when you see the film. It's a complicated set of feelings to be entertained by awful things, you know? Which is where the horror dimension comes in."