British twins, James Andrew Eric Phelps and Oliver Martyn John Phelps, who play the Weasley twins Fred and George in all the film versions of the Harry Potter series, are scheduled to arrive in Taipei Monday for a four-day visit, filmmaking sources said Sunday. They will be the first Harry Potter cast members ever to visit Taiwan. During their stay, they will promote the 'Harry Potter and the Deathly Hallows' -- the seventh and final of the Harry Potter films based on novels written by British author J. K. Rowling. The film will debut in Taiwan Nov. 19. The twins will also tour the Taipei International Flora Expo, famous night markets, the Chiang Kai-shek Memorial Hall in downtown Taipei and other tourist attractions, the sources said. 