Sir Michael Caine has hinted at the plot of new Batman film The Dark Knight Rises.

The 78-year-old actor, who plays Batman's butler Alfred, joked to movie blog Collider.com that director Christopher Nolan has made the cast sign the Official Secrets Act, but appeared to reveal Batman may have a partner such as Robin, or Catwoman, played by Anne Hathaway in the film.

Caine said: "It's fantastic. As the butler, I do a load of filming at the beginning, and everybody goes off and does all the adventures and they all come home shot to pieces and I patch them together when they all get back."

The British star, who is reprising his role from Nolan's first two Batman movies, revealed the director is so strict about keeping the film secret, he ticked him off for even revealing he had been cast in the film.

Caine said: "We've all signed the Official Secrets Act. I'm lucky to be able to tell you the title of the movie. I remember I did an interview and someone said to me, 'What are you doing next?' I said, 'I'm doing Batman."

I saw Chris and he said, "Why did you tell them you were doing Batman?" I said, "Because I am." He said, "You're supposed to keep it secret." I said, "I couldn't keep that a secret."

"Let me tell you... the plot is extraordinary... really extraordinary. I know why he wants to keep it a secret. You really need not to know till you see the movie."

Source: Press Release