You'll remember her from her stark and near silent scenes with Heath Ledger in "Brokeback Mountain" when, playing the role of Jack Twist's mother, she hesitantly welcomes Ledger to her home. But the quiet Wyoming farmer's wife in the simple housedress that Ledger meets in that film is as far from the everyday reality of actress Roberta Maxwell as it's possible to get. Great actors possess the ability to completely transform themselves, and it's a tribute to Maxwell's almost supernatural talent that you can't find a trace of the character she played on the screen when you meet her in person. In her career to date she has acted alongside stage and screen legends like Anthony Hopkins, Julie Harris and Susan Sarandon among many others. This week she's readying herself for a new role that would challenge any actress, a starring role in the New York premiere of "The Shape of Metal," the new show from noted Irish playwright Tom Kilroy that begins previews on September 8 at the Theaters. Playing Nell Jeffrey, an Anglo Irish artist and mother who's at once capable of great evil and great sensitivity, she casts a large shadow over the stage and everyone about her. Her relationship with her two daughters Judith, who remains by her side, and Grace, who vanished 30 years earlier never to return, forms the core of the play. While "The Shape of Metal" is a stimulating exploration of the nature of art, and of the demands society places on the artist, it is also an intimate and moving portrayal of three women in one family. It's also Kilroy's most ambitious plays in years. "What attracted me to the play was having Tom Kilroy say, 'I think I have a play for you.' Those words are like gold," Maxwell said during a recent interview with the Irish Voice. "I read it and I thought, My God, this work is so huge. I mean not just the play, but also the psychology and the mindset, the technical problems of speaking his language. "I came back to him and I said, 'It's a fantastic play. I must find someone to do it.' Finally George Heslin (the Irish-born artistic director of the Origin Theatre Company, who is producing the play in association with the Irish Department of Foreign Affairs) said, 'This play is for you.'" One of the main reasons Maxwell originally wanted to keep the play at arms length was that there are aspects of the character that she understands so well they were actually discomfiting. "Some people are civilians and some people are artists. If you're on the outside, there are complications that can arise that would not otherwise. There are aspects to this character - her incomprehensible rages, for example - that are very Irish, and that I can identify with." As she rehearses the play the scale of the devastation unleashed by her character is coming more and more into focus - and it times it takes her breath away. "I think my character has great love for her daughters. But I think I am just starting to understand the depth of ownership - her idea that they are really extensions of her, she does not see them as having a life outside her. "One of her big problems is that her daughter has come back to confront her with a secret, an action that my character has taken that is pretty reprehensible, that has caused a lot of damage. It's exciting to explore these themes with another actor, to explore that give and take as characters." Maxwell, like her character in "The Shape of Metal," is Anglo Irish. Her family home for nearly 200 years is Ballincard House in Birr, Co. Offaly, where she has returned frequently throughout her adult life. "I can transpose my character's house in the play to my own family house very easily. Even the walk to her studio is easy to imagine because that's my own life, that's my own world," she says. "My father came to Canada in 1927. But originally my family came from Scotland and eventually they moved to Offaly. We had a small 300 acre farm there since the 1700s. And Birr was always a stronghold of the IRA, so I'd always dreaded getting into that issue with the Catholic people in the village. "But I finally asked a woman who was very senior in the village what the situation was with my family in the early 1920s, why we weren't burned out. 'Oh, she said, that's because your family had a history of being very pro-Irish even though they were Protestant.'" Although her family was spared the worst excesses of the Irish Civil War, Maxwell's father decided to leave Ireland during that tumultuous period. "He had to leave. He and his father had gelded some cattle, which broke a general strike in the area," she says. "That Sunday at church a young man came up to him with, opened his hand and showed him a bullet. 'This is for you, Maxwell,' the young man said. My father left in 1924. "When I went back for the first time in 1960 to visit my aunt and uncle who had remained in Ireland, a man dressed in black with a black hat appeared at the end of the driveway. My aunt was very frightened but my uncle was not. The man came up and shook my hand and said, 'I want to meet Robert Maxwell's daughter.' "I had no idea who he was or what was going on. But it turned out this was the man who had threatened my father; he had been a member of that group at the time. And now he was here to shake my hand. It had all came around in a circle." Maxwell often visited Ireland in the 1960s when she was in her twenties, and these days she returns yearly. "I don't have any brothers or sisters here. My family all live in Ireland and I plan to return there this December after the next two shows I'm scheduled to perform in end their runs." For Maxwell, working with Ang Lee and Heath Ledger, two of the most respected film directors and actors in the world, on "Brokeback Mountain" was a recent highpoint. "Making that film was a great experience. And watching it, when my face came up on screen, was a shock for me. To see that the pain in that scene - which is so raw - and then the scene's direction, which is flawless. Heath Ledger was so deeply involved with his character, you couldn't help responding to his presence." Asked what she hopes audiences will take away from her performance in "The Shape of Metal," Maxwell replies, "The truth in a family and in a relationship must be pursued no matter what the cost. Every family has secrets, and even when it seems impossible to get there you owe it to them and to yourself to unravel them, otherwise you'll forever be enmeshed in secrets and lies." ("The Shape of Metal" officially opens on September 12, and runs until September 30 at Theaters, 59 East 59th Street in New York. Call 212-279-4200 or on the web at www.ticketcentral.com for tickets.)