For decades, American and British celebrities have appeared in television advertisements that air exclusively in foreign markets. Though popular opinion has swayed in recent years, there was a time when a star—especially from the film or music industry—was considered a has-been or a sell-out if seen in an ad. If nothing else, it was considered tacky behavior for an A-lister or a rock star. But there’s big money to be made in non-English speaking countries like Japan, and with contracts specifying the spot only air in that country, for many it’s too good of an...