As I mentioned was a possibility, Eddie Murphy has stepped down as Oscar host following the exit of Brett Ratner:
Academy of Motion Picture Arts and Sciences President Tom Sherak announced that Eddie Murphy has withdrawn as host of the 84th Academy Awards. "I appreciate how Eddie feels about losing his creative partner, Brett Ratner, and we all wish him well," said Sherak.
Commented Murphy, "First and foremost I want to say that I completely understand and support each party's decision with regard to a change of producers for this year's Academy Awards ceremony. I was truly looking forward to being a part of the show that our production team and writers were just starting to develop, but I'm sure that the new production team and host will do an equally great job."
Previously...
Eddie Murphy Seen as Possible Casualty of Ratner Oscar Departure [tr]
Brett Ratner Out as Oscar Producer Following Anti-Gay Slur [tr]