I wonder if Anthony Welsh knows that having lunch in front of a journalist inevitably means that whatever he’s eating will get a mention in the article for absolutely no reason at all. It’s sushi.

We’re at the English Touring Theatre rehearsal space where he’s working on debbie tucker green’s latest, heavily guarded play, nut. Immediately recognisable from his performances in Blackta at the Young Vic and Roy William’s Sucker Punch at Royal Court Theatre, Anthony find himself in an awkward position today. Unable to reveal much about nut or his role in the play, he’s somehow got to plug it.

Lucky for him (and me), he’s not only highly articulate and really easy-going but he can back up everything he says with a solid understanding of tucker green’s writing. That knowledge will prove useful when he stars alongside Idris Elba and Nicola Walker in debbie’s first foray into film, Second Coming.

It’s almost ten years since she won the Olivier for Most Promising Newcomer for born bad, a psychologically complex play about two generations of one family confronting abuse. born bad was particularly distinctive because of its fragmentary structure and its redolent nature. It, like her later plays: dirty butterfly, stoning mary and truth and reconciliation, left audiences shaken. It’s something Anthony recalls when he talks about the power in her writing.

“Did you see truth and reconciliation?” he asks, “I watched that, it was a matinee performance too but I came out of it and felt like my day was done.” Is the intensity of truth and reconciliation something we can expect with nut I wonder? “I don’t know if it’s going to be intense,” he insists, “I’m just suggesting that it might be.”

The plot is only hinted at on the National Theatre Shed’s website with a quote from the play “Bein’ you means not bein’ me, see, a deficit already – before you even started we running at a loss.” So I hazard a guess and ask Anthony to tell me how far off I am. I’m thinking something Kafkaesque, I tell him, maybe something about constructing our own identities and paring them down in order to move forward. But when I put this to Anthony, I get sort of a half-smile in response.

“It’s basically centred around one woman,” he explains, “you stay with her, she has visitors and I play Devon, one of the visitors. It’s about how she interacts with those people and how she navigates her own way through her life. So maybe you’re not too far off.”

“The most difficult thing about this piece” he continues, “is how specific it is. I think that’s the case with all of debbie’s writing. Everything in the script is there for a reason. There isn’t a dash or a dot or a comma or anything that is not supposed to be executed and it gets tricky when you’ve got a few characters in one scene and our lines are quite bitty. You can start something, get cut off and then have to go back to that sentence you started three lines later.” He might find it rough but he’s noticeably exhilarated by debbie’s distinctive poetic style. “Her work is very rhythmic and quite Jazz-like,” he says of her poeticism, “so there is structure but you’re allowed to play. Thing is, you can only play once the structure is completely embedded in you.”

We talk a lot about working with structure and characters, whether an actor should bring themselves to the role or bring the role to them and how insular one can be about a particular part. “With debbie’s writing in general,” he says, “you can extrapolate so much from it. There are lines that suggest that my character might do something or come from somewhere but it’s so open to interpretation that my version of Devon will be totally different to someone else’s version of Devon.”

His final words on his own performance can double as a summation of the best way to approach a debbie tucker green play, especially one with almost no synopsis: “I think you have to draw on your own experience because that’s what make you you. The imagination is the best place to go to.”

nut runs at National Theatre Shed from 30th October until 5th December.