Previous Underground Cinema themes have included LA Confidential (seen here) and Spirited Away. Photo: Cameron Zegers
Don't bother asking where the next Underground Cinema event will be held. Or what film will be screened. Or why guests have been instructed to wear their finest toga.
Apart from a few picturesque shots of deserts on social media sites and an ancient Roman theme, a level of secrecy surrounds the event that would be the envy of immigration minister Scott Morrison.
You can't tell who are guests and who are the actors.
''We try [not] to give many clues,'' says creative director Tamasein Holyman. ''Everyone likes to guess the film and we'll guide you in the right direction but we might send you in the wrong direction as well.''
Underground cinema - noir LA Confidential. Photo: Cameron Zegers
Teasingly, she suggests Gladiator and Ben Hur as possible films, and cryptically offers a new clue: ''We'll be exploring the theme of belief.''
Keeping guests in the dark sounds like a strange way to put bums on seats. But Holyman says Underground Cinema, in which the world of a film is recreated prior to its screening, attracts up to 2000 people each time it is staged in Sydney and Melbourne.
''Our guests get dressed up 100 per cent to a point that you can't tell who are guests and who are the actors,'' she says.
A different location is used for each event: Sydney Boys High School was transformed into The Swedish Academy for Forensic Sciences prior to the screening of horror film Let the Right One In, while the University of Sydney's chemistry building was turned into a police precinct that mimicked LA Confidential. In Melbourne, Underground Cinema has been staged in places as diverse as Albert Park Lake and Donkey Wheel House in the CBD.
The last event recreated the Louisiana bayou prior to showing Beasts of the Southern Wild, with guests told the theme was water and to dress Cajun-style and wear gumboots.
A text message sent one day before the show last November revealed the location to be the Sydney Heritage Fleet boat yard in Rozelle, where guests encountered a creole band playing off the back of a ute, a crocodile in a swimming pool and were served hot gumbo and drinks in jars.
They were then ushered into a school room and given survival tips by teachers including one wielding a snake. In the Crab Shack they were met by yokels drinking and telling tales of the last flood, before encountering ladies of the night singing sweet southern lullabies and dancing slowly with guests to live music until the film was screened.
''In all the scenes, we treated the guests like children the same age as the protagonist Hushpuppy in the film,'' Holyman says. ''But like the film we never spoke down to them. We made sure they were tough and learning to survive out there.''
Underground Cinema's 60-strong acting troupe devised characters who could have inhabited the Bathtub community alongside Hushpuppy, improvising scenes inspired by the Oscar-nominated movie.
The company also has a backstage crew of more than 200, mainly volunteers who work to create the elaborate worlds guests later watch on screen.
Actor Mike Sutherland was one of the moonshine-swilling yokels, creating his Smart Jimmy character from scratch. His previous outing saw him having fist fights and interrogating suspects as Guy Pearce's detective character from LA Confidential.
Sutherland says performing with guests can be a challenge, depending on their level of enthusiasm and willingness to become part of the show. He has jumped into dumpsters and almost had to strip at the water-themed event.
''I was clowning around with the audience when someone yelled 'Just take your clothes off','' he says. ''I looked at the supervisor, hoping he would stop it, but he just told me to get on with it.''
Sutherland took off his shirt but was saved from revealing more flesh by the start of the movie.
Another guest proposed to his partner in front of friends and actors playing characters based on the animated Japanese film Spirited Away during an event at Melbourne's Chinese Museum.
The enthusiasm of guests, no doubt lubricated with liquid refreshments that are in the spirit of the theme, continues during the film screenings, Holyman adds. ''The audience gets excitable as a group and reacts to moments in the movie, especially when they see a familiar scene or character they've met.''
In 2007 in Britain, Secret Cinema pioneered immersive theatrical experiences inspired by movies. Its latest event asked guests to don 1930s-style attire, learn to waltz and check in to an interwar-era hotel based on Wes Anderson's new film The Grand Budapest Hotel. Filmgoers have conducted mock scientific experiments before a screening of Prometheus and experienced life behind bars before sitting down to watch The Shawshank Redemption.
Artistic director Fabien Riggall says people are seeking out real experiences, rather than passive forms of entertainment.
''Why I think this works is that people dress up, they feel relaxed, they talk to people they might not have met at a cinema,'' he told Time Out London. ''It's a social experience.''
Holyman staged her first clandestine film screening in Melbourne in 2009, attracting a few hundred people. More than 30,000 people are now signed-up members of Underground Cinema, thanks to word-of-mouth.
She admits guests have to take a leap of faith in buying a ticket to an Underground Cinema event, since they do not know what will be in store. ''We give our audiences something others don't,'' she says. ''By not revealing everything, we open people to the experience.
''We allow people to stay open-minded, take off their judgment hat and just be in the moment.''
Underground Cinema presents Rome in Melbourne March 21-23 and in Sydney on April 5 and 6. Details: undergroundcinema.com.au