Alexander Skarsgård and Nicole Kidman had never worked together before they united to play husband and wife on HBO’s Big Little Lies—a high-wire act in which the actors summon a textured, toxic marriage, replete with graphic violence, passionate sex, and a disturbing combination of both. (What Skarsgård and Kidman accomplish is all the more impressive considering they make up just one story line in an ensemble series limited to seven episodes.) The two actors did, however, have one mutual experience that uniquely prepared them for the task at hand.

“Nicole and I have both worked with Lars von Trier,” Skarsgård said by phone on Wednesday, referring to the controversial Danish filmmaker who doesn’t shy away from the disturbing—be it sexual, psychological, or experimental. Kidman starred in 2003’s Dogville and Skarsgård in 2011’s Melancholia. As the actor pointed out, Jean-Marc Vallée—the French-Canadian filmmaker who directed Big Little Lies—“works in a similar way—with existing lights and a hand-held camera that is constantly on the move. It’s not a traditional filming experience in that there is a master shot. You don’t block scenes. It is very liberating as an actor. Every take is different, and you can try new things without being restricted to tape marks on the floor. It helped us, especially for those very emotional and physical scenes.”

Kidman, who also executive-produced the series, has said that she was adamant about casting Skarsgård. “I wanted him! I wanted him badly,” the Oscar winner told Vulture last week about the Swedish actor, whose breakout role was as a vampire in HBO’s True Blood before he achieved title billing this past summer in the $180 million Legend of Tarzan. According to Skarsgård, he and Kidman were on the same page from day one, when they took what author Liane Moriarty had written in her best-selling novel and what screenwriter-producer David E. Kelley put in the script, then hashed out a plan for a psycho-sexual pas de deux that television audiences had never seen before.

“I wasn’t familiar with the book when I got the script, but I was really intrigued by this relationship,” explained Skarsgård. “I felt that it was an opportunity to tell a story about an abusive husband that wasn’t a stereotypical two-dimensional character—it was a chance to find someone who is genuinely, deeply struggling with his demons. We had a couple weeks before we started shooting, and I spent time with Nicole working on our relationship—discussing where we wanted it to go and how to portray the marriage, in terms of making it more interesting and more confusing in a way that was fascinating for the audience.

“We wanted to show how sexual their relationship is, and how that bleeds into the abusiveness, and how the interconnectedness of those two things make her blame herself for him being so abusive. That’s one of the reasons it takes her longer to realize she can’t be with him. At the beginning of the series, she still sees that innocence in him.”

For those intense scenes—whether they were sexual or abusive—Skarsgård explained, “It was all about building that trust, finding your connection, jumping off the ledge, and seeing where it takes you.”

Kidman has said that the physical scenes were, in fact, so physical that she left set with bruises. Her decision to go Method was partly because of Vallée’s documentary style of filming, and partly because she “wanted to tap into the truth of” what women actually go through in these relationships. As Celeste and Perry, both Kidman and Skarsgård would tap into such places of passion, darkness, and intensity for those scenes that Skarsgård admitted “it was definitely tough shaking that off.”