Gary Oldman has let slip a major secret for the next Batman movie - the Riddler will be the major villain.

The forthcoming The Dark Knight features The Joker and Two Face, with the original plan being - SPOILER ALERT - that the Joker would feature again in the following film.

But assuming that movie bosses don't cast again following Heath Ledger's death, there's a space for another one of Batman's nemeses to appear on the big screen. And Oldman has revealed that it's The Riddler's turn. Jim Carrey last played the character in Batman Forever.

Not that Oldman doesn't think it is a particularly bad idea for another actor to play the Joker.

He told Movieweb, "I don't see why not. I mean, they did it with Katie Holmes' character (she is being played by Maggie Gyllenhaal). I understand that this is a different circumstance, but I think another actor could do the job. I think Heath would want another actor to do the job.

"Maybe we don't need the Joker. Because we'll have The Riddler."

Oldman was more coy about whether he will feature in the third film following reports that he was less than happy to reprise his role as Lt James Gordon in The Dark Knight. "I guess I have to come back. We all have to."