'It's funny that the body remembers these kind of traumatic events,' Miller told ET.
Sienna Miller brought her real-life experience to her latest role. The 40-year-old actress stars in Netflix's Anatomy of a Scandal as Sophie Whitehouse, a wife and mom who's thrust into the spotlight when her politician husband is accused of rape.
Miller herself is familiar with becoming tabloid fodder. Her one-time boyfriend, Jude Law, made headlines in 2005 for having an affair with his children's nanny.
"The tabloid media was really intense and really rife. There was very little agency that young woman had over their own lives and the telling of their stories," Miller told ET's Lauren Zima. "Getting the call one evening that something was coming out in the press the following day, and it had gone to print, and there's nothing you can do about it, and it's intensely personal and painful and everyone's gonna know, is a horrible, horrible feeling that I and many others experienced in the earliest part of my career."
Miller noted that revisiting those emotions for the role "was uncomfortable," and made her "recalibrate the memory, in some way, of some of those events."
"My heart started beating really fast in one scene and the monitor that I had on for the sound picked it up. They've actually kept my accelerating heartbeat as a motif throughout the show, and certainly in that scene," she said. "It's funny that the body remembers these kind of traumatic events."
However, Miller noted that there was also "catharsis in all of it."
"I often find [that after] going to work and getting to cry or explore things psychologically, I go home a bit lighter," she said. "It's free therapy sometimes."
In addition to relating to the barrage of press interest that her character goes through in the series, Miller identified with Sophie's desire to protect her children at all costs. Miller is mom to a 9-year-old daughter, Marlowe.
"In my experience, when you have a child the instinct is to protect them from everything. That kind of comes naturally being a parent," Miller said. "[Sophie's] first response is, 'How do I protect my children from this?' Which I understand and of course can relate to... She's doing everything to hold this family together. This family is everything she's given her life to and it's crumbling, and the children are kind of innocent players in a really unpleasant plot."
While the plot may be unpleasant to live through, Miller is hopeful that it will make for an exciting viewing experience for fans.
"It's just exciting to not only make something that's compelling and compulsive in the way that this is, but also really looking at the themes... it added up to make it more substantial than just something compelling," Miller said. "It's quite thought provoking."
Anatomy of a Scandal is now streaming on Netflix.