There are a number of Hollywood stars lending their talents to Black Ops II. Sam Worthington returns as Mason, for example. The only thing Worthington provides, though, is his voice.
Others got to be in the game. You might recognise Admiral Briggs as Tony Todd, while Harper bears a resemblance to his voice actor, Michael Rooker. My favourite, though, is veteran actor James Hong. While cast as the Chinese Premier, he plays the Chinese Premier, providing not just the voice but the face for the character as well.
Seeing his face come out of nowhere—it's a lot of trouble to go to for an incidental role!—near the end of the game was awesome, as I'm a big fan of Hong's, from his famous "Brade Runner" role all the way through to his show-stealing performance in Kung Fu Panda.
Interestingly, it's the third major game this year Hong has starred in, as he not only appeared in Diablo III but also put in a great performance as the ageing Uncle Po in Sleeping Dogs.