There are a lot of things hidden in Man of Steel. Our Superman expert Jeff Taylor has already compiled a big, two-part list of Easter eggs and references to other Superman incarnations and the DC Comics world at large. Some of them are just fun production design (there's a Waynetech logo on the satellite Superman and Zod destroy), others are characters with bigger importance in the comics (one of the kids bullying Clark Kent becomes the villain Conduit). This, however, is even more subtle than all of the ones we already know about.
An eagle-eyed Redditor has uncovered what they think is a cameo by Christopher Reeve. It comes at the moment Superman enters the gravity-increasing beam of the World Engine and looks up. It's during that moment where Henry Cavill's face morphs, ever so briefly, into Reeves' face. You can check that out below and judge it for yourself.
What do you think? Is that actually Reeves' face? Or do you think it's just wishful thinking on a fan's part?