According to BBC News Twilight Star Robert pattinson is said to be taking over as the Doctor after the 50th Anniversary show and the Christmas special in which the current Doctor, played my Matt Smith will regenerate.
Robert previously said he would be eager to take up the role.
EDIT; Yahoo news also reported it.
EDIT: Unfortunately as much as we would love for this to be true, this was our April Fools prank. Well done to all of you that figured it out!