5. Ed Harris - Gravity
Given that Sandra Bullock and George Clooney are pretty much the only actors in this year's visual effects masterpiece Gravity, it'd be easy to miss the fact that - yes - Ed Harris also features in the movie, too. Harris, who has obviously been cast here due to his associations with Apollo 13, provides the voice of Mission Control back home on Earth, and can be heard chatting with Clooney and Bullock at the beginning of the flick. If you've seen Apollo 13, then, you'll know that Harris played pretty much the exact same role he does here in Apollo 13 (he was Flight Director Gene Kranz), except we actually got to see his face in the latter movie. So if you happened to recognise his dulcet tones whilst you were immersed in Gravity, good for you - most people probably didn't even consider the fact that Alfonso Cuaron took the time to set-up this little in-joke.