So it was John Hurt who revealed to the world initially that he would serve as the "missing link" we didn't know existed between the 8th and 9th Doctor, and now it seems like he might have let another cat out of the bag. This comes from a quickly deleted tweet Hurt sent recently in reference to Peter Capaldi.
Congratulations Peter Capaldi. I'm suboth and we will have a lot of fun.
The tweet after deletion was quickly followed up with...
“Congratulations to Peter Capaldi and to the BBC. Another splendid Doctor!”
While it's still somewhat cryptic as to what the deleted tweet meant (typo, possible true name of character) it seems as though John Hurt will be sticking around for more episodes than just the 50th. Why? Because Peter Capaldi isn't appearing until Smith's regeneration of course! Or is he?! Who knows with Stephen Moffat. Thanks Primetime Unreality for the heads up!