She joins Zac Efron, Michelle Williams and Zendaya on the project. Michael Gracey is directing from a script by Michael Arndt. Jenny Bicks wrote an earlier draft.
Chernin Entertainment and Laurence Mark are producing. Production is set to begin in the fall.
Justin Paul and Benj Pasek, who were Tony-nominated for “The Christmas Story,” are writing original songs for the film. Kira Goldberg is overseeing the project for Fox.
The project has been in development since 2009 with Jackman attached to play the showman, who rose from humble roots and was able to hoax a gullible public, as he created the three-ring Barnum & Bailey Circus that made him famous. Barnum gained fame as a 19th century impresario with tours of Tom Thumb and Lind; he began calling it the “Greatest Show on Earth” near the end of his career.
Ferguson, who broke out in “Mission: Impossible — Rogue Nation” last year — will next star in “The Girl on the Train,” due out Oct. 7 from Universal. She will also star in Daniel Espinosa’s “Life,” opposite Ryan Reynolds for Sony and Tomas Alfredson’s “The Snowman” opposite Michael Fassbender and Chloe Sevigny for Universal.
Ferguson is repped by ICM Partners and Tavistock Wood.