Actors have a recurring nightmare, Christopher S. Carroll says: “You’re doing a show, you haven’t rehearsed, there are people there, and you just accept the circumstances and try to bluster your way through.”

Blank, by Iranian playwright Nassim Soleimanpour, has echoes of that nightmare. Over the next month (Mill Theatre at Dairy Road, 3-24 February), Mr Carroll and four other solo performers will act in a piece they have never rehearsed, and whose script (kept in a sealed envelope, its contents a secret until then) they only see when they come onstage before an audience. Moreover, the script is full of blanks, which the actor fills in based on the audience’s wishes.

“This type of work pushes the idea of theatre all together,” producer Lexi Sekuless says. “It completely breaks the fourth wall, but the level of participation between performer and audience creates this amazing bond.”

This is the second time the Mill Theatre has opened its season with a play by Soleimanpour; last year, Ms Sekuless produced his award-winning White Rabbit, Red Rabbit. That was a political play, written to travel around the world when Soleimanpour, at the time unable to leave Iran, could not; while Blank is a warmer piece about the human spirit and human connection, Ms Sekuless says. But neither are plays the actor can rehearse.

“To have a show where the whole conceit is that the actor walks in and essentially it’s a cold read is incredibly appealing,” Ms Sekuless said. “It’s unlike anything else. It’s still theatre, but it’s very flexible.”

And challenging and exciting to perform, to boot. Ms Sekuless likens Blank to an acting masterclass: the actor needs plenty of courage, supreme confidence, possession of language, and vocal dexterity. Each of the five performers will bring a different technique to the script, including physical theatre and improvisation.

“I don’t know what’s going to happen on Saturday,” Mr Carroll (headlining the show, on 3 February), said. “Usually, I’m in a position where you’re like ‘I’ve worked on it; we’ve been rehearsing; and this is what you can expect’. In this case, of course, I don’t know what to expect…

“Often you want the safety net when you’re performing, having rehearsed it so many times, and … practised [the play] within an inch of its life.

“But I think that I’m at a point for myself as a performer and as a writer, as a maker of theatre, where I feel confident that I can engage with whatever is thrown at me, whatever the playwright is looking to achieve, and bring my own technique as a performer and … what the rules of the game demand.”

Mr Carroll, Irish-born and French-trained, is a specialist in Movement for the Actor.

“The actor’s instrument is the body,” he explains. “This is all you have to express whatever it is, or to channel or to respond, and you really want to have no barrier between the inner world, between the impulse or what’s happening imaginatively, what’s happening emotionally, and the audience.”

Like an athlete, he will keep limber through physical training before the show, so that his body will respond to his impulses and intuition on the night – even, if he so wishes, turning a somersault.

Mr Carroll has been called “the master of the solo performance” – a genre he regards as “the ultimate challenge”.

“It’s wonderful to be on a set with other people, and to have the surprise of another performer to feed off, their energy – but in a solo show, the relationship with the audience becomes intensified; they are your scene partner,” he said.

“You really get to know yourself a performer, warts and all, through that process. Every single solo show I’ve done has been its own kind of Everest, its own sort of psychological excavation… And there can be something so demanding that you just set this huge kind of mountain for yourself that if and when you can rise to it, it’s exhilarating.”

Stefanie Lekkas (10 February), a Greek-Australian actress originally from Melbourne, also has a background in physical theatre. This will be her second time performing a work by Soleimanpour: she performed White Rabbit last year.

“I had never done anything like that before,” Ms Lekkas recalls. “Prior to coming onstage, I was handed an envelope and opened it, and it was all a little bit of a blur. But it was a lot of fun.”

Having performed a Soleimanpour play once, Ms Lekkas was eager to do another. She finds his unrehearsed approach freeing, compared to plays that are rehearsed for months, and where the actors know their characters and lines inside out.

“There’s no expectation that you’ve read that line 50 times and decided where to put the stress and the emphasis,” Ms Lekkas said. “It’s raw, and it’s in the moment – and I think we could do with a little bit more of raw and in the moment.”

She will prepare by practising turning pages. “That’s harder than it sounds, and I remember doing a bit of fumbling with the last one. Because you can’t prepare for what the theme is; you can’t try to prepare for the nature of the show, the physicality, the vocal quality; you can’t prepare for a storyline or character development … Because of all these unknowns, the only thing that I really know I need to practise is turning pages!”

The other performers are Ali Clinch (17 February), Heidi Silberman (23 February), and Sarah Nathan-Truesdale (24 February).

Audiences should see different performances, and compare the actors’ techniques; the performers (once they have had their turn) will.

“I’m really looking forward to seeing how they approach the work,” Ms Lekkas said. “The one that I saw last year that wasn’t mine was very different; it was like watching a complete other show. And the funny thing is that it was the same script!”

The Mill’s 2024 season includes Helios, straight from the Edinburgh Fringe Festival, and on its way to the Adelaide Festival; a revival of an Australian play, The Shoe-Horn Sonata, written to lobby for a memorial for nurses on Anzac Parade; another participation play, Terror, in which the audience are the jury at the trial of a military pilot; two sequels to shows staged last year: Reasons to be Happy, “incredibly biting yet wildly realistic”,and the Rockspeare Henry VI 2; Eurydice, a retelling of the Orpheus story; and Canberra playwright Peter Wilkins’s Chalk Pit, a true-crime story about a murderous MP.

Mr Carroll also leads Canberra Youth Theatre’s Emerge Company, a training program for emerging actors and theatremakers aged 18–25, who create their own work as a company. This year’s program will begin in March. To enrol, visit: https://canberrayouththeatre.com.au/emerge.

Blank, by Nassim Soleimanpour, 3-24 February, 7.30pm, Mill Theatre at Dairy Road; hosted by Lexi Sekuless Productions. Tickets: $40 to $45; available: events.humanitix.com/blank-february-2024-theatre-at-dairy-road.