The chief writer is leaving the show at the end of this year's specials and will be succeeded by Steven Moffat.
Meanwhile, Tenth Doctor David Tennant will be replaced Matt Smith in the title role.
Davies told The Times: "People are going to be Doctor Who-deprived this year, so it's got everything in it: CGI monsters, prosthetic monsters, army, police, an alien planet.
"It's our last chance to have a bit of a laugh. Now the Doctor's facing the end of his life, it's going to get dark."
When asked if there would be a dry eye in the house after his last episode, he said: "I should f**king think not!"