Assuming you don't book your passage during a full moon or contract norovirus while enroute, this might actually happen:
http://www.princess.com/cruise-tips-vacation-ideas/video/onboard-experience/stars-commercial.html#.VLGqXNLF-HQ
http://www.princess.com/cruise-tips-vacation-ideas/video/onboard-experience/stars-commercial.html#.VLGqXNLF-HQ