ROYAL CARIBBEAN INTERNATIONAL will allow its guests to dance onstage as part of "Invitation to Dance," the line's newest production show. As part of the show, put on by the creator of the ABC hit "Dancing with the Stars," four couples on the Explorer of the Seas will be chosen during a ballroom dancing event at the beginning of each cruise to participate in the show later that week. Professional dancers, stylists and makeup artists will prep them for the event. The couples will then join the Royal Caribbean cast on stage and compete against each other for the applause of fellow guests in the audience.