The X-Men actor was apparently filming a dramatic fire rescue scene for the P.T. Barnum biopic at the Brooklyn Navy Yard in New York in the early hours of Sunday morning when there was a problem with the pyrotechnics. Six large lights, which were used to exaggerate the glow of the movie blaze, then fell from a roof in a specially constructed building, causing the fire to spiral out of control.

“Fire was blowing out through the roof,” a fire source told the New York Post. “It blew right through the roof and melted a lot of really large light fixtures on the top.”

According to the site, five retired firefighters, who had been hired to work as movie firefighters, helped tackle the blaze by attaching prop hoses to nearby fire hydrants until around 100 real-life professionals appeared on the set at Flushing Avenue and Navy Street. They reportedly struggled to extinguish the fire as it had become so enormous.

“The fire was tremendous,’’ another source said. “They used too much accelerant, and the whole building burnt down.’’

In the final scene, Hugh was supposed to carry Zac from a burning building before the fake firemen put him on a stretcher. The Australian actor was reportedly one of about 150 people present on the set but it is not known if Zac was there at the time. A representative only told the Post, "He’s not hurt.”

Hugh plays Barnum, the famous conman-turned-showman who founded the Barnum & Bailey Circus troupe, and Zac plays his assistant in the musical. The movie, which also stars Michelle Williams, Zendaya Coleman and Rebecca Ferguson, is due for release in December (17).