JOHN KIELTY grimaces when asked when he'll get his hair cut.

The actor is not at all excited by the prospect of having his now long hair the length favoured by early 20th century Irishmen.

"I'm not keen," he says, forcing a smile on to his face.

"I only get a haircut when I absolutely have to, so I'm leaving it to the last moment."

But the haircut trauma is the only area of reticence John has about his latest acting role.

He's hugely excited about appearing in new Oran Mor play, A Terrible Beauty, in which he stars as Irish freedom fighter Michael Collins.

Written by Rab C. Nesbitt creator Ian Pattison, the story focuses on the last few days of Collins' life, revealing the incredibly fractious, divided world where the nature of nationalism is debated.

The debate focuses on whether the IRA should accept the offered treaty with Britain.

And the play reveals the story is as much about the personalities involved, the infighting, as it is the idealism

Of course, it will resonate with Scots audiences, given the closeness of the referendum.

"It's a great play," says John.

"It's also daunting to play such a character because people have strong feelings about Collins. His boots will be hard to fill."

Michael Collins was from County Cork, which is where the Kieltys came from.

"I've never been but I've got three weeks off in October and I plan to go to Ireland," says the second generation immigrant.

"It's all down to working on this play. It fills you with a real understanding of the era and the country."

John adds: "My passion is Scottish history, the Reformation and the divisions in this country. But this play has made me think about Irish history."

John has become engrossed in the world of Collins; what motivated the man who was head of intelligence with the Republicans, how determined was he to seek peace?

MAJOR General Dalton said of Collins, 'He's too keen for a compromise for the sake of a healing'.

"The thing about Collins is he was always seeking a common ground.

"He was also a religious man and isn't the crux of Christianity being nice to other people? But you get the impression from the play some were not prepared to put their own feelings aside for the healing."

The narrator of the play is a young Glasgow revolutionary who was part of the George Square riots and went over to Dublin to fight the cause. Collins warns him off his idealism.

"Collins says at one point, 'If you're not careful, you'll end up stabbing your best friend and kissing your enemy in the backside."

David MacLennan, the late Oran Mor producer, wanted the play staged in the run up to the referendum.

"He was aware of how this story would resonate," says John. "We can already see the divisions in Scottish society."

John has been working hard on his Irish accent.

He said: "Cara Kelly, an Irish actress friend, has been keeping me right. And I'm sure there will be people in the audience who know the difference between a Cork accent and Dublin accent so I can't just do something that sounds okay."

The actor brings huge passion to every performance, and indeed every play he co-writes with younger brother, Gerry.

Together they have created the likes of Oran Mor play The Murder of Geoffrey Robins and The Onion of Bigotry, which ran at the Edinburgh Festival and told the history of the Christian Church from the Declaration of Arbroath on. A big ask?

"It was," he says, smiling. "And sometimes my plays come out to mixed reviews. And I know you have to have a thick skin in this business, but that's something I don't have."

But the passion for the theatre - which began at school in Cumbernauld and continued at Coatbridge College - remains.

Along the way to becoming a professional he was pushed and encouraged by director Liz Carruthers, who is directing A Terrible Beauty. "Liz was always involved," he says. "She's been a great supporter."

The director will know how to get the best Collins out of John Kielty. All he has to do now is have a haircut.

"It has to go," he says, flicking his fingers through his locks. Michael Collins would have thrown himself out of his own army if he'd had hair like this."