How about we wait until the episode airs to find that out, shall we?
But, in my opinion, it would be REALLY weird if he was.
No, he isn't. There was a filming picture of his WITH the Doctor, Amy, and Rory.
As it turns out Yes the dreamlord is the Doctor, or atleast the Doctor's dark side
______________________________________________________________________________________________He's basically the modern series equivalent of the Valeyard. Shame Michael Jayston didn't return.