Nicole Kidman has spoken out about the impact that filming The Undoing had on both her physical and mental health.

In the critically-acclaimed Sky Atlantic drama, Nicole appears opposite Hugh Grant as Grace Fraser, a therapist whose world is rocked when her husband is accused of murder.

In a new interview on the podcast WTF With Marc Maron, the Oscar-winning star revealed that the show’s more intense scenes took their toll on her mentally, which in turn led to her becoming physically ill.

“On The Undoing, it kind of happened where I just was like… suddenly, I was in this place, there was sort of a disquietness to my personality where I was uneasy, and there was duress on who I was,” she explained.

“I actually got really sick, and I think this is a big thing that happens to actors. I went down for a week because your immune system doesn’t know the difference between acting and truth when you’re doing those.”

Explaining how difficult she finds it to shake off certain roles, she continued: “I have not learned a technique to tell my brain and my body, ’Oh this is just acting’. I haven’t learned how to clean that out.

“It doesn’t really work for me. I go home, and I don’t sleep well and I’m not well if it’s that disturbing to me.” 

Offering her much-lauded role in the 2018 film Destroyer as another example, Nicole added: “That was awful… I stayed in that character.

“I didn’t want it to feel like acting. I would growl and moan. I was a very unpleasant person during that time.”

The Undoing received rave reviews from critics when it debuted last year, and had the biggest launch for a US show on Sky ever, beating a record previously held by Game Of Thrones.

Listen to Nicole’s full interview on WTF With Marc Maron.