The music was critical to the film’s realisation. Luhrmann uses contemporary music to instil in the audience the notion that the Moulin Rouge is the sexiest, wildest nightclub in the world where the most dangerous and electric dances are performed on stage. That meant that a rehash of the traditional can-can just wouldn’t do it for today’s audiences. “But if you hear Fat Boy Slim’s music…,” says Luhrmann, helpfully…

What is more, the popularity of many of the songs helps to ground the film, according to executive music producer Anton Monstead, even if they are sometimes rearranged, like The Police’s ‘Roxanne’, which is done as a tango. Or ‘Diamonds Are a Girl’s Best Friend’ à la Kidman; or Bono with T-Rex’s song, ‘Children of the Revolution’. The first single, ‘Lady Marmalade’, is already a disco hit, but has been reworked, as has Nat King Cole’s ‘Nature Boy’, with David Bowie and Massive Attack. And McGregor teams with Placido Domingo for Elton John’s ‘Your Song’. Clearly, Moulin Rouge is not your average musical. But, insists Luhrmann, our familiarity with the basic musical material (and lyrics) makes for accessibility.

The bit we’ve all been waiting for: the can-can number. But, like everything else in Luhrmann’s Moulin Rouge, it’s done to a distinctively different beat.

The film also stars John Leguizamo as Toulouse Lautrec, who plays cupid to the two lovers. “I've read a lot of biographies of Lautrec… he was the product of first cousins and very wealthy, but he had a lot of defects, so his parents stopped having children after him,” says Leguizamo, who studied the painter's life and spent time learning about his background. “He was born a dwarf with an enlarged tongue, so he spoke with a lisp, drooled a lot and had big sinus problems. He was a decadent little man who loved attention. He loved to be noticed, and he found a way through partying. He loved to drink and he drank himself to death. Well, he died of syphilis and absinthe poisoning! I’ve tried absinthe: it’s wild stuff! It’s like drinking acid - it burns a hole right through your gut.”

Lautrec’s short stature meant that Leguizamo had to work on his knees, with little stilts attached. But, since Moulin Rouge is a musical, he had to dance as well, and his knees took such a beating that the actor had to use sticks when walking about off the set.

Nicole Kidman on set with director Baz Luhrmann.

Apart from the two male principals and British actor Jim Broadbent as the nightclub’s impresario, Zidler, the ensemble cast is largely Australian, comprising the Bohemians (Bohos) in ringleader Toulouse’s gang, with Garry McDonald as the hallucinogenically inspired Doctor; Jacek Koman as the tango-dancing Unconscious Argentinean; Matthew Whittet as the composer, Eric Satie; and David Wenham as writer Audrey.