On two-show days, what do actors do between performances? Some of them, if they live close to the theater, go home. Others take a long walk or work out at the gym. Still others nap. Rachel Griffiths, starring as Brooke Wyeth in "Other Desert Cities," is in the third group, as I discovered when I dropped by her dressing room at the Booth the other day between shows. 

Given the level of focus required to play Brooke, recovering one's energy with rest makes perfect sense. "She is an intense character," Griffiths said of this daughter of an actor turned Republican politician. "She's been in a superfragile state her whole life. When she enters the hospital and has to be taken care of for all those months it wasn't just a psychological breakdown. It was a narrative breakdown. Getting out and then writing the memoir about her family is her way of recovering that narrative." Mentioning a radio interview she heard recently with the Israeli novelist David Grossman, Griffiths remarked: "He said that the role of the writer is to shine a light into dark corners no one else is examining. Brooke is trying to do that." 

Griffiths, who was born in Melbourne, Australia, and came to international attention in the 1994 film "Muriel's Wedding," said: "Brooke confronts the truth that nobody else wants to look at." She continued: "Real-life daughters of American political alpha males - look at the Cheneys, the Bushes - tend not to rebel. Brooke is unusual in that respect." Why does it take Brooke so long - until she is in her 40s - to begin to unearth the facts about her personal history? "Part of the reason," Griffiths said, "is that she is close to her father. That keeps her contained for many years, long after the tragic events concerning her older brother." 

Griffiths said that perhaps the biggest challenge in playing Brooke is understanding the character's "myopic self-righteousness. I realized that this is in part the privilege of the artist without children." Griffiths, who herself has a son and two daughters, explained: "It's not an original thought but it is very true that with children your perspective changes. The balance between art and life shifts." 

While making her Broadway debut in "Other Desert Cities" (the last time she was on a stage was in a Melbourne production of "Proof," with Naomi Watts and Heath Ledger), Griffiths has had to make some practical adjustments to her art/life balance. Referring to her acclaimed work on the American TV series "Six Feet Under" and "Brothers & Sisters," she said, "During the past ten years I was in L.A. getting up at 5:30 in the morning. In New York, I've had to invert that schedule: staying up later and getting up later." 

In other ways, Griffiths said the relationship between stage and TV is parallel. "I always say that my work in TV feeds what I do in theater. In both cases, I have to handle a lot of language. Unlike in movies, where generally speaking there is less text." 

Griffiths, who said that getting her vocal technique back to optimal shape for stage took about a month after preview performances began in October, appreciates the demands, textual and otherwise, of "Other Desert Cities." "The play is so beautifully constructed. Robbie" - the playwright, Jon Robin Baitz - "has given us something wonderful. And the audiences really appreciate the gift. They have been so attentive. It's extraordinary." 

Brendan Lemon is the American theater critic for the Financial Times and the editor of lemonwade.com.