Rihanna has been appointed to sing on Royal Caribbean`s Oasis of the Seas on November 19. The Barbadian songstress` performance will be a part of the special three-night preview voyage scheduled for the 5,400-passenger vessel before the world`s largest cruise ship is officially debuted in early December this year. Beside celebrating the ship`s debut, this gig will also become one of Rihanna`s efforts to promote her new album "Rated R". She is scheduled to take the stage at Oasis of the Seas` outdoor AquaTheater, which is an unusual amphitheater-style space that serves as a pool by day and ocean-front theater by night. Rihanna`s other planned concert will take place on the album`s release day on November 23. On the particular day, she will visit ABC for "Good Morning America" performance. Moreover, she is rumored to perform at 2009 American Music Awards.