Hunt & Darton call their cafe a slice of interactive performance art. Others, on arriving to see two fine art graduates from Central St Martins with broccoli and pineapple on their heads and serving teas and coffees, might see something different.

Still, the pop-up cafe opening in Brighton Square next week will certainly be an eccentric alternative to the city’s collection of cupcake coffee shops.

Jenny Hunt and Holly Darton’s Open Surgery is to be the official hub and meeting place for people involved in the month-long series of events in SICK! Festival. The festival explores “the medical, mental and social challenges of life and death and how we survive them (or don’t)”.

Responding to SICK!’s remit, the duo have invited medical practitioners to be waiters at their cafe to offer visitors diagnoses with their coffee.

“We always invite people to come and wait on tables for the day,” explains Darton.

“They can respond to that role creatively. For this project we have invited some doctors and nurses – along with academics, artist and local groups – to be our guest waiters.”

As Hunt points out, when your lunch is served you can also ask about that knee you’ve had a problem with for a while.

“The GPs will get to enjoy the project first,” says Darton. “And then after it will be on their terms as much as ours.

“They’ll be serving the customers and talking to the customers. How much they do depends on how the customer responds.”

Interactivity is the key. When the duo started off performing theatre together as Hunt & Darton eight years ago, they hated the traditional divide between actor and audience in theatre space.

They wanted to perform in a more subversive way and be closer to their audience.

So they created a cafe scenario which closes the gap between performer and the audience.

The first pop-up space opened in 2012 in Cambridge. It was commissioned as part of the Cultural Olympiad.

Darton says they are “taking theatre to the high street to reach a broader range of people and audience development, to engage more people in the arts”.

You can drop by for a coffee without interacting and it will be a subversive experience, she adds.

But you’ll still be part of a giant art work, with every detail, from the furniture to the menu, decided by the two artists.

“We see the entire cafe being an artwork, with its components decided upon in the same way as if we were making a painting or a sculpture.”

The themed days will certainly get punters involved.

If it’s the Health And Safety Day, customers might have to wear an apron and a hair net.

Austerity Day is an attempt to make people understand the value of what they are eating.

“We try to encourage people to spend less and, if they could, potentially share that day. Also, we replace all the ornaments in the cafe with potatoes.”

On Community Day, everybody is encouraged to sit together and all are introduced to each other.

“If a new customer comes in, they are introduced to the whole cafe and you have the opportunity to buy a trifle or a quiche which would feed the whole cafe for £10,” says Hunt.

“We also have the Not Great British Bake Off that day, in which we have a competitive event to make a sugar sandwich. The criteria include movement, literacy and absurdity.”

Expect to pay around £5 for lunch, with roast dinner sandwiches, roughage plates, beans on toast and Blue Riband biscuits all on the not-for-profit project’s menu, which is inspired by the pair’s 1980s childhood and gran’s biscuit tin.

The set menu is three courses not for consumption, reveals Hunt.

“They are titles, almost like titles of a poem, and we perform either spoken word or movement – they are usually quite humorous.

“Some are vignettes, or haiku, short poems or moves we do in synchronisation. For example, Jockey is a move we do where we both simulate being a jockey on a horse. That is a main course option.”

  • 16 Brighton Square, Brighton, Wednesday, March 5 to Saturday, March 29. Open 11am to 7pm, closed Sundays and Mondays. Visit huntanddartoncafe.com