If you're interested in editorial portraiture in general and celebrity portraits in particular, you probably already know about the teNeues magnum opus of the work of he's-everywhere man-o'-the-moment Martin Schoeller, who I don't know and about whom I know nothing. I don't really care for Martin's Sunday-magazine style much, to be honest, although I certainly admire his level of accomplishment and work ethic, from my vantage point way down here in the foothills far below the snowy Olympian peak he inhabits.
Vincent Peters (same publisher) is a bit more to my own taste, although I don't know much about these genres in general. "How can a photographer of internationally known stars create iconic portraits that linger in the memory—especially since these actors have already been photographed and filmed millions of times?" asks the blurb—and then answers itself by saying that Vincent Peters "relies entirely on the classic art of portrait photography for his pictures."