Just because you've starred in more Christopher Nolan films than any other actor doesn't mean you get to know Christopher Nolan's secrets.

Just how secretive are Christopher Nolan movies? Not even Michael Caine knows anything about Nolan’s upcoming espionage action film “Tenet” and he’s featured in the cast. Not only that, but Caine is also a close friend of Nolan’s and one of his most frequent collaborators, having appeared in eight of the director’s blockbusters.

In a new interview with The Hindu, Caine says Nolan wouldn’t even give him the “Tenet” script to read. “All I had was one day’s work and he gave me my pages,” the actor says. “I did my part and shot only with John David [Washington]. I haven’t heard anything since.”

Caine and Nolan’s long-running collaboration got its start when the actor joined “Batman Begins” in the role of Bruce Wayne’s butler Alfred Pennyworth. Caine said of his first meeting with Nolan, “He came to the front door of my house in the country with a script. I could see him through the glass but I couldn’t recognise him. The moment he introduced himself, I knew exactly who he was because I was a great fan of his three small films.”

When Nolan pitched Caine on the idea of having him join “Batman Begins” as Pennyworth, the actor initially scoffed at the idea because it sounded as if it would be a minimal supporting role. “I told him, ‘I am too old for Batman. Do you want me to play the butler? What would my dialogue be? Would you like another beverage or more custard?’”

Nolan convinced Caine to change his mind by describing his vision for the Alfred character. In Nolan’s film, Alfred would serve as “the foster-father of Batman” and not just the family butler. Caine agreed and would go on to appear as Alfred opposite Christian Bale’s Batman in both of Nolan’s sequels, “The Dark Knight” and “The Dark Knight Rises.” Caine adds, “I did the movie and it was one of the greatest things I have done in my life.”

Outside of Nolan’s “Tenet” and “Dark Knight” trilogy, Caine has also appeared in the director’s “The Prestige,” “Inception,” “Interstellar,” and “Dunkirk,” the latter being a voice-only cameo. The upcoming “Tenet” stars John David Washington and Robert Pattinson as spies who somehow have the ability to time travel. Warner Bros. is releasing the film nationwide July 17.

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