There has been a rumor about a certain Batman Begins actor returning for The Dark Knight Rises, which, up until this point, hadn't been fully confirmed or denied, but it did make some fans upset about spoilers. So, tread carefully, as we are about to enter Major Spoiler! territory.
Way back in /the-dark-knight-rises-features-a-resurrected-ras-al-ghul/June, an unconfirmed source reported that Liam Neeson had been spotted on the set of The Dark Knight Rises reprising his role as Ra's Al Ghul. It wasn't known at the time if this was a flashback or if the character is being resurrected from the dead. Then in /liam-neeson-confirms-presence-on-the-dark-knight-rises-set/January, Liam Neeson confirmed that he was on the set, but he was only there for an hour and a half. Which, if you know anything about filmmaking, isn't nearly enough time to shoot a substantial scene. Many took the first sighting as the actor simply visiting the set to see old friends.
Now, it is Warner Bros. themselves who've confirmed that Liam Neeson is in fact in the movie. The studio issued production notes for this week's Wrath of the Titans to the press, which contained the following information about the actor.
"Neeson next appears in Peter Berg 's actioner Battleship, and he also will be seen in Christopher Nolan 's much-anticipated action thriller The Dark Knight Rises"
Chances are, Liam Neeson's short amount of quoted time on the set was simply the actor being coy (there is no way he could have shot his scenes in an hour an a half). It is still not known if Ra's Al Ghul will be appearing in a flashback, a dream, or if he has crawled out of the Lazarus pit. That info is being saved for the first time you watch the movie.