At the Skyfall press conference a couple of months ago, director Sam Mendes refused to say who some of the actors in the movie would be playing, suggesting that to do so would be a bit of a spoiler.
One of those mysterious roles is who Ralph Fiennes is playing, but now Movieweb suggests they've got a well placed source at the studio who's let it slip. So if you don't want to know, stop reading now.
Fiennes recently said in an interview he'd be playing a government agent, and now Movieweb's source says, "Ralph Fiennes play's a government agent, which we never get a name on, because he is set to play the new M. Skyfall centers around M (Judi Dench) where her past forces her to leave as head of MI6, and find a new M. The board of MI6 then turns to a government agent (Ralph Fiennes) to take over. M (Dame Judi) is now forced to train the new head of MI6."
At the moment this should be treated as rumour, but Movieweb's stick by its source.