One could be forgiven for thinking Brian Ferguson has just seen a ghost.

As he takes a lunchtime break from rehearsals for Dominic Hill's new production of Hamlet, the actor playing the title role looks suitably haunted and not a little drained from the experience.

"It's so big to do," says Ferguson. "I didn't really know, as a part, what it actually meant. Obviously every actor knows the name Hamlet and the character of Hamlet, but I was not very well versed in the play. I have not seen many productions of Hamlet, so cracking it open has been mind-boggling, really, to get the opportunity to crawl around inside it has been incredible."

Ferguson will not be drawn on Hill's approach to the play, nor to what his own interpretation of Hamlet may end up as. All he will admit to at this stage is that, as the publicity photograph of him backed into a corner sporting a contemporary dark suit on the show's flyers suggest, "It's not done in period, but we are starting from the text, always from the text. And I think that is one of the things to discover about how incredible it is, as you start uncovering what the text is doing, the pictures it is painting, and what it wants of a scene in terms of the relationships.

"We are playing with the form a fair bit, we are playing with sound quite a lot, and we are being quite bold, I suppose, in how far out we are going in terms of trying out ideas. So the world we have created is not set in any particular time. There is no strict concept on it, and we have kind of gone the other way, and are being quite imaginative in how we are exploring it, and allowing it to suggest whatever it suggests. I still do not know where it is going yet, but the flavours Dominic enjoys as a director are great for this, and are very much the same places I like to go as an actor."

Ferguson thinks long and hard before he chooses his words. He does not want to give the game away about the production, and, as he has already indicated, he is probably not entirely sure what that game is yet. When he does find the right words, they sound like poetry, and what comes through them is just how much he is relishing exploring such a rich and complex play, as well as the equally intense character he is in the thick of finding out about.

"When Shakespeare wrote Hamlet there were big changes going on in society," Ferguson says. "The chivalry of Elizabethan society and the knights were giving way to trading companies.

" There was also this big change in religion, going from Catholic to Protestant, and going from God being almighty and powerful to thinking about reason. The idea of Heaven and Hell was still very real. Heaven was up in the sky and Hell was beneath your feet, and what that does to your imagination, and how colourful and vivid that makes the world of the play, is really exciting.

"One of the challenges of doing Shakespeare, and one of the things most exciting to someone like me, who has done a lot of new writing, is coming into this alien world where there is no subtext. It is all, all, all in the language and the pictures he paints with words, and the journeys they make you want to go on. So it is a very different process. It feels like a more physical process as an actor. Heaven and Hell are things I don't have a connection with today. I was brought up an atheist, and there are things in Shakespeare that, 415 years after it was written, do not mean as much. But sometimes you have to make your peace with the fact the words you are saying might not be understood."

This is not the first time Ferguson has appeared in Hamlet. Aged 17, he played Polonius in a Scottish Youth Theatre production. It was while at SYT, which his mother had taken him to, that Ferguson decided he wanted to be an actor.

While at drama school, he made his Citz debut playing bit parts in Stewart Laing's production of Mae West's little-seen drama, Pleasure Man. His first professional job was also at the Citizens, in former artistic director Giles Havergal's production of Frank McGuinness' play Observe The Sons Of Ulster Marching Towards The Somme. After a year out of work, Ferguson came into his own in Davey Anderson's debut play Snuff.

"I felt like I had grown up a bit when I did Snuff," he says. "I guess it felt more immediate and important to me, which was important to me as an experience and a compass. I suppose after a year out I had more of an idea of what it was that I was excited about as an actor. The things I felt strongly and more passionate about had been put to the test."

Subsequently, Ferguson has worked with Poorboy and was cast in Black Watch and Dunsinane, David Greig's sequel of sorts to Macbeth. He has also appeared at the Traverse in Edinburgh and the Royal Court in London. Such diversity, he says, "is my lifeblood" and acting in general is a serious business.

"It is about seeking a deeper connection," he insists. "It is a place where I get to move at the pace I enjoy moving at, and get to ponder over things, and play and discover things. It gives me that space, and to do that with other people in that space, to explore and be in that place together, that's the point."

Hamlet, Citizens Theatre, Glasgow, September 19-October 11.