Nicole Kidman

Nicole Kidman says playing this character had 'disturbing' side effects

The actress opened up about her role in The Undoing

Eve Crosbie

Nicole Kidman has opened up about the disturbing impact her role in HBO's hit drama series The Undoing had on her. 

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In the series, Nicole plays Grace Fraser, a psychologist whose picture-perfect life falls apart when her husband is linked to the death of Elena Alves, a fellow parent at their son's private school. 

Speaking about the hit HBO drama series on the podcast WTF With Marc Maron, the actress revealed that getting into character for the show took a toll on her health, both mentally and physically.

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WATCH: The Undoing was a hit when it aired in December

"On The Undoing it kind of happened where I was suddenly in this place of... There was sort of a disquietness to my personality, where I was uneasy and there was duress on who I was," she said. 

The 53-year-old actress then revealed that she got "really sick" during filming for the hit HBO thriller. "I went down for a week," she said, adding: "Your immune system doesn't know the difference between acting and truth when you're doing them.

MORE: The Undoing viewers saying the same thing about the show's finale

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MORE: Nicole Kidman teases The Undoing season two

"I have not learnt the technique to tell my brain and my body that it is just acting," she continued. "I go home and I don't sleep well, and I'm not well. It's that disturbing to me."

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Nicole said she was left "really sick" because of the intense role

The gripping six-part HBO series concluded with the discovery that Grace's husband, played by Hugh Grant, really was responsible for Elena's death all along, despite convincingly protesting his innocence.

Despite Nicole's comments, both she and co-star Hugh Grant have expressed interest in reprising their roles of Grace and Johnathan Fraser for a second season. After the show's last episode aired, Nicole penned a tribute to the cast and crew of the HBO show and gushed, "Greatly looking forward to working with all of you again," while Hugh recently teased that there is "more story to tell" about the characters.

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Both Nicole and Hugh have teased a second season of the hit drama series

"I think there's certainly more story to tell about Grace, and my son, and Grace's dad. I don't know exactly what I'd be up to, just in prison," he told Digital Spy. "I don't know how that develops. I mean, you'd have no whodunit, because we now know who did it. You'd have to find some other thing to keep you interested."

Although the show, which was based on the novel You Should Have Known by Jean Hanff Korelitz, was billed as a limited series, it wouldn't be the first series to move beyond its source materials. Notably, Nicole's other HBO series Big Little Lies returned for a second season following the events of the book.

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