Bairbre N∅ Chaoimh, the Dublin-based actress/ director who has performed with most of Ireland's larger theatre companies, and made regular appearances at the Abbey Theatre, and whose directing work includes the phenomenally successful Catalpa, is still associated in the public imagination with two things. "It's either Bosco or Glenroe," she says rue-fully. "One or the other."

However, there is rather more to N∅ Chaoimh than being the presenting sidekick of a red-haired puppet on children's television. In 1999, she was appointed artistic director of Calypso Productions, the theatre company founded by Donal O'Kelly and Charlie O'Neill in 1993 to produce issue-led theatre.

Does N∅ Chaoimh really think theatre can be an instrument for social/political change? "I don't like agit-prop - that doesn't interest me," she says simply. "But I passionately believe that artists can be a catalyst for change in society. I think all theatre deals with social and political issues . . . everything human beings do." Is she idealistic?

"I do love the innocence of things shining through. I would try to embrace idealism; but you have to fight." N∅ Chaoimh is not na∩ve. But what primarily interests her in her work with Calypso is "human beings in relation to the world". The next Calypso show, Look Who's Coming to Dinner, is a case in point - a Dublin version of the famous American film with Sidney Poitier, written by Roddy Doyle.

The original film, which explores the underlying racism of white liberal America, is, in Doyle's version, set "right in the heart of Dublin". The main character is a working-class Dub whose unconscious racism comes to the fore when his daughter brings home a Nigerian asylum-seeker.

Though a comic character, he is still sympathetically portrayed, something which N∅ Chaoimh believes is very important if people are really to engage with the issue.

"Most people aren't racist in the stereotyped way . . . the real danger is in people's fears and mis-understandings." Quoting Mary Robinson's challenge to look inside ourselves, she says she wants audiences to put themselves in the shoes of the father character and ask themselves some difficult questions.

N∅ Chaoimh hopes the production will bring this issue to a wide audience - and also that Roddy Doyle's name might encourage people who might not normally go to the theatre to come along.

"Roddy Doyle does have mass appeal . . . anybody who can make you laugh can't be intimidating!"

This commitment to accessibility runs throughout N∅ Chaoimh's directing work. For someone who unashamedly admits that she still holds her breath when she goes into the theatre, she wishes that more people could have access to it.

"Theatre, without intending to, tends to become exclusive. People are afraid to walk into the Abbey or the Gate - they are afraid they won't know how to behave." She loves to make her work accessible and she loves comedy, often finding it in the least expected of places: for example, her production of Yerma for Gallowglass Theatre Company, which cast puppets alongside actors, resulting in an surprisingly comic version of Lorca's awkward tragedy.

"Puppets are a fantastic way to tell stories - turns us all into children." Her recent production of The Star Child and Other Stories - a staging of Oscar Wilde short stories - introduced her non-puppeteering actors to not one but three different puppetry techniques.

This kind of playfulness, and the introduction of unorthodox methods, is typical of her work. Calypso's last production, Gavin Kostick's The Asylum Ball, which she directed last year for the Dublin Theatre Festival, used a very theatrical staging to highlight issues of mental health and schizohrenia. The challenge for N∅ Chaoimh was how to "depict psychosis on stage". Her solution: to use heightened visual effects and physical theatre techniques in order to let the audience into the mind of a psychotic character, to see what he sees: one minute we see a normal girl at the Trinity Ball, the next we see a 9ft woman in a ballooning gown full of faces.

Prior to the production, N∅ Chaoimh worked with a group of schizophrenics and is obviously fascinated by them.

"They have the most incredible imaginations . . . they experience episodes . . . almost like tripping." It is this sense of "heightened reality", as she calls it, that interests her.

So, is that what theatre is to her - a kind of heightened reality? "It can be," she says eventually. "At its best . . ." She claims to be uninterested in the "star system thing", which bores her to death. What she likes is collaboration and adventure and a sense of the ensemble. It is therefore, perhaps, no surprise that she particularly enjoys working with "adventurous" actors like Donal O'Kelly. She describes the award-winning Caalpa, O'Kelly's hugely popular one-man show, as "an adventure from the beginning".

Together, O'Kelly and N∅ Chaoimh set about working out how to stage and dramatise such a huge and ambitious story: making it theatrical, playing around, trying things out. It is obviously a way of working she enjoys.

"You come up against a wall - then the wall becomes the inspiration." She believes Catalpa's universal appeal is due to "the combination of a brilliant script along with the simple, accessible and playful way it's presented: it's based on what children do in their bedrooms, playing games in their imaginations."

N∅ Chaoimh is in Galway at present to direct The Spirit of Annie Ross, her first production for Druid Theatre Company. Penned by Bernard Farrell, the story of four characters who agree to spend a night in a "haunted" house for charity is, of course, a comedy. But N∅ Chaoimh insists it has its darker side.

"Well, it is about spirits! People think Bernard writes really funny plays, but if you dig under the surface they are quite terrifying."

She admits it is a novelty for her to be in rehearsals with a finished script already in place. But she considers it a luxury to have the writer in rehearsals, and Farrell himself has been "incredibly flexible."

So can we expect to see evidence of her usual imaginative approach? She is giving little away, but admits to a few add-ons.

But where does her fertile imagination come from? She does not hesitate. "You have to have a sense of mischief, a sense of fun about life - a sense of humour."

The Spirit of Annie Ross opens at the Town Hall Theatre, Galway, on Wednesday