The 31-year-old, who has appeared in Billy Elliot in Sydney and on Broadway, was reportedly recruited from the US where he was working as chief choreographer for Disneyland in Anaheim.
Horner told The Daily Telegraph: "My experience is with Australian ballet and musical performance across a broad field so I'll be bringing something different to the panel."
The Australian dancer was brought in after it was announced that judge Mark Wilson would be leaving the show. Wilson said that it was the Seven Network's decision to "recast" his role and said that he "understands" that TV shows need to "evolve".
Horner will join Todd McKenney and Helen Richey on the judging panel.
Contestants in this year's series include My Kitchen Rules chef Manu Feildel, singer Damien Leith, Home and Away actor Dan Ewing, golfer Jan Stephenson, sports star Nathan Bracken and model Lara Bingle.