Not many shows tell potential audience members, "lower your expectations".

But for their seventh show, Green, Australian comedy duo The Umbilical Brothers have done just that, adding, "The plan is to try out new stuff, this is a work in progress people."

Consider that fair warning if you can't stand anything less than a fully-fledged show. But for others, what's lost in polish might be gained in spontaneity. There's also the fun of witnessing how a show is created - and the feeling of helping contribute to the development, since audience response is obviously vital in live comedy.

Canberrans will have the chance to see the "work in progress" where no two performances will be identical. The final version of Green will tour next year.

David Collins - who, with Shane Dundas, forms The Umbilical Brothers - says, "We want all of our shows to be different from each other, using different technology."

For this show, they are employing two green screens showing various imagery. The Umbies might find themselves in space, on the TV show Survivor, or in the middle of a Baby Apocalypse, among other scenarios. The audience has the choice of watching the performers on the green screens in the created environments or on a sparsely populated stage looking rather odd in their movements and gestures and expressions. And, of course, they can alternate between the two for an even more surreal experience - especially if Collins and Dundas's rehearsals fail them and they go out of synchronisation with what's on screen

Joining the duo on stage is Doug Bayne. What's he there as?

"Batman's nemesis!"

That was an unexpected turn. So, will Collins be Batman?

"God, no! If it were me I'd be Robin."

In fact, Bayne is "a visual effects master" who is in charge of the green screen technology, providing the various digital backgrounds against which the Umbies can do their thing - a mixture of mime, dialogue, slapstick, puppetry and voice effects.

While there is a sizeable high-tech aspect to this show, Collins wants to make clear that it is all live ("And that includes me!") - there is no pre-filming.

"It's absolutely, 100 per cent live, would you believe?"

Any doubters will probably be convinced when a camera goes into the audience and shoots, putting images of the people watching on the screens and making them part of the show.

Collins is pleased to hear The Courtyard Studio is an intimate theatre space. In Sydney, the Umbies were in a theatre that seated several hundred people and Collins says he doesn't like it when it feels like people aren't able to see everything the performers are doing.

The Umbilical Brothers have had considerable international success for nearly 30 years Sydneysider Collins and Canberran Dundas met in Sydney in 1988 and things moved on from there. As well as their live stage shows, which have toured internationally, they have made many TV appearances, had a Logie Award-winning children's program, The Upside Down Show, and done voice work for film and television, among other gigs.

Although they spend a lot of time together, Collins says, "We both do separate things when we can."

He's recently appeared in the TV series Drop Dead Weird ("I played a zombie"), the horror movie Red Christmas ("I wanted to die onscreen") and the TV movie The Oxford Circus (as "a fat, sweaty man").

But it's The Umbilical Brothers for which he and Dundas are most famous and the Umbies are far from finished.

After their two-week Canberra season they'll be going to Paris, Switzerland and Slovenia, among other destinations, presenting some of their previous shows in different cities.

And no doubt, in due course, Green will be added to the repertoire.