In a jokey speech introducing clips from the movie at the Las Vegas movie convention CinemaCon, the Logan star insisted he had to audition. His rival for the role was Chris Aronson, the 20th Century Fox executive who kicked off the presentation by donning a tuxedo, top hat and flashing lights to perform with a dance group.

"I was only up against one person," Jackman said. "Chris. I got the role. I won the role fair and square."

According to Variety, the clips featured Michelle Williams, who plays P.T.'s wife Charity Barnum, ballroom dancing across the New York City rooftops; Zac Efron, who plays a trapeze artist, tapping on the counter of a bar; Zendaya doing calisthenics on a trapeze; and bearded ladies singing and dancing.

It's the directing debut for Australian Michael Gracey, whose background is in commercials and visual effects.

Jackman described it as "a fantastical rags to riches tale" and a celebration of "creativity and what is unique about each and every one of us." It centres on the idea that Barnum introduced the modern concept of showmanship as a 19th century entrepreneur.

The movie features songs and music from Justin Paul and Benj Pasek, who won an Oscar from two nominations for La La Land, and the Broadway hit Dear Evan Hansen.

Jackman joked that he discovered Pasek and Paul before they worked on La La Land, adding "not that I'm competitive."

Saying that the movie took seven years to bring to the screen, Jackman argued that big swings were the way to keep the movie business competitive in the Netflix and YouTube era.

"This movie is about taking risks??? and that is what is going to propel this business," he said.

The Greatest Showman opens on Boxing Day.

For Jackman, it follows up the success of Logan, which has taken $US569 million ($745 million) at the worldwide box office.