Eugene O'Neill's autobiographical play Long Day's Journey Into Night is widely considered to be the Nobel laureate's masterwork.

First performed in Stockholm in 1956 (three years after the Irish-American dramatist's death), the Pulitzer Prize-winning drama had its British premiere at the Royal Lyceum Theatre, as part of the Edinburgh International Festival, on September 8, 1958, in a production starring Alan Bates as Edmund Tyrone (the Eugene O'Neill role) and, to great acclaim, Gwen Ffrangçon-Davies as Mary Tyrone (the barely fictionalised mother character).

Now, some 55 years later, the play returns to the Lyceum stage and, once again, it has an acclaimed actress playing the female lead. Diana Kent has starred in such celebrated screen works as Peter Jackson's film Heavenly Creatures and Nick Murphy's thriller The Awakening. On stage, with the Royal Shakespeare Company and Bristol Old Vic, she has performed many classical texts, including modern classics by great authors such as Arthur Miller and Tom Stoppard. It's a professional biography which almost cries out for the addition of O'Neill's play.

As its enigmatic title suggests, the drama charts a day in the life of an agonisingly dysfunctional family, the Tyrones, which is closely modelled upon O'Neill's own. The character of Mary Tyrone is meticulously based upon the author's mother, Mary O'Neill, née Quinlan. Addicted to morphine, she lives a life which is parallel to those of her husband and sons.

James, the nominal patriarch, is an alcoholic, penny-pinching Irish immigrant actor and one-time matinee idol, who squandered his undoubted talent on long runs of mediocre, money-spinning plays staged as a vehicle for him. The sons, Edmund and James Jr, also alcoholics, are locked in a downward spiral of mutual jealousy and wasted potential.

When I meet Kent at the Lyceum (where Long Day's Journey opens on January 17), she tells me that she is drawn towards both O'Neill's writing and the character of Mary. "When you read the play, you realise how amazingly forgiving O'Neill is of everyone in the family," she says. "There's no baddie in the play. Everybody is flawed, everybody damages everybody else, but there's a reason for it, and everybody can be forgiven. It's a hugely compassionate play."

While everyone in the piece suffers, Mary is a character apart. First, as a woman, she is pushed to the margins of the male-dominated and alcohol-driven life of the family. Moreover, she is less responsible for her addiction (which was the consequence of being prescribed morphine by a doctor during childbirth) than are her menfolk.

"I feel immense compassion for her," says Kent. "There's a bit of a Princess Diana scenario going on there. She marries this older man. She comes from a convent. She has no frames of reference. She just thinks she's got this amazing catch."

Like every art work that deserves to be proclaimed a "classic", Long Day's Journey achieves a resonating universality despite - perhaps because of - its very specific origins. Everyone, at some level, can feel elements of their own lives in the anguished relations which unravel onstage. "Living the life that they all lived was awful," suggests Kent. "It was absolute Hell on Earth to be within that family. People struggle with that all the time, living with family members who are addicted and disappearing behind the addiction."

Even if one has been fortunate enough to have lived a life untouched by addiction, the pain O'Neill felt at the loss of his mother to morphine is something which, the actor believes, everyone can empathise with. "The fallout of living with somebody who is actually not there anymore is huge," she observes. "That's especially true if it's a mother. We never stop being children to our mothers. The need for a mother to look after you doesn't go away when you grow up. It's a fundamental part of our life experience. Not to have that is devastating."

Kent's enthusiasm for the play is anchored firmly in her tremendous faith in O'Neill as a writer - a faith which she contrasts with her feelings towards the playwright's major influence, the great Swedish dramatist August Strindberg. Recently, she was on the verge of performing in Strindberg's play The Dance Of Death, but the project was abandoned.

"I kept reading the play and asking myself, 'How much do I trust this writer?' I have to be honest and say, in the end, I didn't. I read it in four different translations, and I kept thinking, 'I think he needed to go back and work on this again.' By contrast, what I feel about Eugene O'Neill is that I trust his writing hugely… You trust that those words are there for a reason, and if you say them the way that he hears them, they work, and that's lovely."

The actor's trust in O'Neill has a gender dimension, she explains. Not every male writer convinces her that a female character is safe in his hands. "Sometimes you read something in which a male writer is portraying a woman's reaction to something, and you don't really believe it. In this case, because the subject matter is in his bones, you trust that the person he's writing about really is the three-dimensional character he has created."

Long Day's Journey Into Night is at the Royal Lyceum, Edinburgh from January 17-February 8. For further information, visit

www.lyceum.org.uk