The four-time Grammy award-winner is to perform at the 5,400-passenger ship's AquaTheater on January 21.
Swift will be on board as part of a seven-night Western Caribbean cruise running on January 16–23.
Entering service on December 1, the new Royal Caribbean International vessel will join sister ship Oasis of the Seas as the two biggest cruise ships in the world operating out of Port Everglades in Fort Lauderdale, Florida.
One hundred winners of a US-based competition and their guests will attend the on board concert by Swift, whose third album Speak Now is released on Monday (October 25).
New entertainment to feature on Allure of the Seas includes a ‘Madagascar’ themed AquaTheater show and the Broadway sow ‘Chicago: The Musical’.