I find it interesting that I'm so prone to going off on tangents about the nature of branding, despite its (at best) tangential relationship to storytelling. Perhaps that's something that can be changed...
Yesterday, Carol mentioned that maybe Michael Jackson's magic powers (or the suggestion of) was one of the things that made young boys part of his audience. I certainly wished I had magic powers when I was a little kid. All that being said though, I don't feel like I can speculate too much on exactly what Michael Jackson's core fantasy is (or at least the core fantasy of “Moonwalker”) without seeing “Moonwalker”, which I haven't done since I was about 6. Still though, we can look at a couple of aspects of it.
First of all, his current condition aside, Michael Jackson is a good singer and an amazing dancer. Without some amount of talent to begin with (all comments about the cult of celebrity aside), it's difficult, if not impossible to become a huge success as an entertainer, and while it's not exactly a one to one correlation, more talent helps.
Second, I think you need to pick an audience that you can actually reach, and nail it. Michael Jackson was less overtly sexual than Prince, so generally given the thumbs up by mothers with teenage daughters, but still “dreamy” enough to be a teen idol. Likewise, whoever concocted the “Moonwalker” magic powers thing delivered on the younger male audience.
Third, I wouldn't say you need to do something nobody's done before, most pop stars, huge sensations or not, don't, but I certainly think it helped Michael Jackson. Is the fact that the movie was named “Moonwalker” not clear enough?
Still though, all of these things make you a pop sensation, not necessarily a larger than life brand. Not only did Michael Jackson start making that jump when he was sold as having quasi-mystical powers, but someone hinted at something very insightful in a comment about Core Fantasies to me a long time ago. Commercials are the most effective when they contain a mini-narrative. My hunch tells me that the reason why people connect with mini-narratives in commercials is the same reason why people connect with anything even vaguely narrative in form.
Next, Music and Narrative: What Makes Interstella 5555 Great.