Andy Serkis has been a subject of much speculation since it was first annoucned that he had been cast in Star Wars: The Force Awakens, but up until now we have only heard his voice in the first teaser trailer. Now, in an exclusive interview with photogropher Annie Leibovitz on the official Star Wars website, new details have emerged about the actor's character.
The character's visual appearance is still in question as the character is portrayed using motion capture technology, although it's possible we have caught a distant glimpse of him in The Force Awakens' second trailer, but the biggest reveal so far is his name and title: Supreme Leader Snoke.
Although this is just speculation, it is easy to infer that Supreme Leader Snoke may be the leader of The First Order, and is therefore analogous to Emperor Palpatine. We also know that Serkis did the voiceover for the first teaser trailer, "There has been an awakening. Have you felt it? The dark side and the light."
From this statement we can also conclude that this is Snoke speaking, and that he is familiar with the ways of the Force; he may even be affiliated with Kylo Ren, who we already know brandishes a strikingly Sith-looking red lightsaber. Further details have not yet emerged, so we don't even know what this character looks like, but it stands to reason that he is most likely not human.
Here's that first teaser trailer with Serkis' voiceover, if you need a refresher: