The Internet Movie Database, admittedly not the worlds most reliable source of information, states that Patrick Stewart was offered the part of Lord President Rassilon in David Tennants final story. If its true, it makes sense. Since the role is initially that of a narrator, it required an actor with a recognizable voice and few voices are more recognizable than Stewarts. He had also worked with Tennant before in a production of Hamlet. Stewart would have been the first Star Trek captain to guest star in Doctor Who. Instead, Timothy Dalton played the part and became the first James Bond to be in Doctor Who.