Hugh Jackman had to be evacuated off the set of 'The Greatest Showman' when a real fire broke out.

The 48-year-old actor was shooting the dramatic final scene of the new film, which also stars Zac Efron, in New York City district Brooklyn at 5am on Sunday morning (12.02.17) when the blaze started after a stunt got out of hand.

According to fire officials and witnesses, Jackman was one of around 150 people at the Brooklyn Navy Yard set when the staged fire spiralled out of control.

But whilst the real-life fire service was on its way, five retired firefighters - who were working as extras on set - sprung into action and attached prop hoses fitted with antique-style nozzles to nearby hydrants to try and battle the blaze, according to a FDNY source.

A source told the New York Post newspaper: ''The fire was tremendous. They used too much accelerant, and the whole building burnt down.''

Authorities confirmed that no one was injured in the blaze.

It is not yet know whether Efron was on set at the time but a representative confirmed: ''He's not hurt.''

'The Greatest Showman' is a musical biopic about P.T. Barnum, creator of the Barnum & Bailey circus.

During the film's final scene - which is being staged in a specially constructed building - Jackman, who portrays Barnum, is forced to carry his assistant (Efron) from a burning house, with the fireman extras placing him on a stretcher afterwards.

But the pyrotechnics used to make the blast look as realistic as possible failed. It is understood that six large lights - used to intensify the glow of the blaze - fell from the roof of the building and sparked an unexpected larger fire, sources explained.

Firefighters rushed to the set at Flushing Avenue and Navy Street but they struggled to put the fire out because it had grown so huge.

A fire source added: ''Fire was blowing out through the roof. It blew right through the roof and melted a lot of really large light fixtures on the top.''