Succession's Sarah Snook And Kieran Culkin Traded A Lot Of Their Lines While Filming

The dynamic sibling duo of Shiv and Roman Roy has been the witty lifeblood of "Succession" since its conception. It might not shock viewers to learn that Kieran Culkin and Sarah Snook have a similar banter in real life that almost perfectly mirrors their characters — save perhaps for the constant back-stabbing. The two actors were so in synch that they would even swap dialogue with one another on-set. Some of our favorite Roman insults might have been written for Shiv, and vice versa. Even though their two characters are very distinct, they share an acid tongue that allowed some of their dialogue to be interchangeable.

Working with Snook is such a joy for Culkin that it doesn't feel like work at all. Acting with his Australian-born co-star feels less like a day of hard labor and more like a fun game of catch — if not a slightly dangerous one.

"I'll just throw at Snook, and she'll catch the f***ing ball and bounce it back at me and elbow me in the face," he explained to The Hollywood Reporter. "It's just the most fun sibling dynamic on the set. We get to play around and be cruel to each other as our characters. That's even more fun because between the two of us, there's nothing but just pure joy and love."

The actors' intuitive tossing gave them each a bit of room to improvise — to drop lines, to pick them up, or even to forget them altogether. "If I f*** up and drop it she'll be like, that's alright, I got the ball, I'll just say your s***," Culkin told IMDb. "There'll be times when I'm like, 'I can't say this line, can you do it?' And she's like 'Yeah, I'll take your line.'"

As Kieran Culkin and Sarah Snook got more comfortable with each other and their characters, they became more fluid with their exchange of dialogue. "We've [swapped lines] a lot throughout the last two years, but this season [season 4] a lot we did a lot of like, 'Would you say these lines, cause I don't want to,'" Culkin revealed. "And she'll be like, 'Fine, yeah, I'll take them, do you want this one?' And I say 'Yeah, I'll take that one.' And we just sort of like play."

Sometimes these changes would happen in between takes, just moments before "Action" was called. "And as they're rolling, I'd be like, 'By the way, I might not say that line. I think something else is gonna come out,'" the "Igby Goes Down" star recalled. "And she'll be like, do whatever you want. And I know that like, she's got my back, so that's a lot of fun to play with."

Culkin has nothing but praise for his on-screen sister. "Snook and J. [Smith Cameron] are possibly my favorite people I've ever worked with in my life," he told The Hollywood Reporter. "I think Snook, in particular, I just feel the most comfortable with doing whatever."

His feelings are definitely reciprocated — Snook also speaks very highly of her "Succession" co-star and similarly revels in their break-neck repartee. ​​"I just bounce off what he says," the actor said, showcasing her immense humility (per Hype). "That man's mind works so fast. And his brain is connected to his mouth with no filter. And so some of the stuff that comes out is appalling and you would never say in public! But you get to say it as Roman. I don't know, it's just always been fun."

In a testament to their like-mindedness, Sarah Snook also used a sports analogy to describe her dynamic with Kieran Culkin. "We just have the same kind of sensibility," she explained. "You throw the ball one way and you know your teammate is going to be able to catch it. And Kieran is always a team member in that sense. He's definitely a team player."

One of the biggest tragedies of "Succession" coming to an end is that Snook and Culkin, who have formed a close bond over the years of filming, will no longer be working together. When the cast learned that season 4 would be their last, Snook teased her co-star in a way that was "probably indicative of the very sibling relationship that Kieran and I have offscreen as well," she admitted to Esquire.

"Hey, Kieran, you'll love this," she recalled teasing Culkin. "When we finish this show, you and I will never work together again." Her typically quick-witted co-star was uncharacteristically wounded by this playful jab. "I went, 'Why the f*** would you say that? F***, I want to cry,'" he recounted. Snook definitely hadn't expected him to take her joke so seriously, but it had clearly struck a chord. "It hit him much more than I thought it would," she said.

On their final day of filming, when Culkin gave a speech addressing the cast and crew of the show, he "mostly talked about Sarah Snook," Esquire reported, "thanking her for their years together as costars; sharing that she's one of his favorite people on the planet and one of his favorite scene partners. [...] And he spoke of his fear that they would never be cast together again."

Here's hoping that a casting director will be wise enough to pair these two dynamos up again soon!