Brian Cox on ‘Prisoner's Daughter’ and Own Daughter Margaret: 'She's Extraordinary' and 'Drives Me Nuts' (Exclusive)

"I love Kate. I really do. I think she's great. She's a real Brit. That's what I love about her," Cox glows to PEOPLE over his costar Kate Beckinsale

<p>Sylvain Lefevre/Getty Images</p> Brian Cox

Sylvain Lefevre/Getty Images

Brian Cox

Succession's Brian Cox plays another complicated father figure in his new movie Prisoner’s Daughter

In the indie drama, the Emmy winner, 77, plays Max, who has been diagnosed with terminal cancer and granted a compassionate release after 12 years in prison. The one condition: he must reside with his estranged daughter, Maxine (Kate Beckinsale).

In an interview with PEOPLE, Cox details his ever-growing friendship with costar Beckinsale, 49, as well as how filming the movie changed his relationship with his own daughter, Margaret.

“I love Kate. I really do. I think she's great. She's a real Brit. That's what I love about her," Cox glows over Beckinsale. "She's got that British sensibility, which is a kind of work sensibility. There's no rubbish about it.”

Prisoner's Daughter doesn't mark Cox’s first time taking up the role of Beckinsale’s onscreen father. “I've known Kate over the years,” Cox explains. “In fact, I did play her father many, many years ago," he continues, referencing their 1994 film, Royal Deceit, which Cox remembers as "terrible."

Sam Santos/Shutterstock
Sam Santos/Shutterstock

Related: Kate Beckinsale on Her Friendship with Brian Cox: &#39;He Doesn&#39;t Like Bull— and I Hate It as Well&#39;

Prisoner’s Daughter tackles some challenging topics such as bullying, healthcare reform and addiction. Despite the dark subject matter, Cox describes the on-set environment as being incredibly joyful.

While filming a pivotal scene, Cox recalls director Catherine Hardwicke (Twilight) jumping feet-first into a pool with her film's stars, Cox and Beckinsale. “She was wearing these shorts, which had what we call in England gussets,” Cox says. “It stretches the clothes. So Kate and I just had hysterics about Catherine's gussets. I have a pillow, which Kate sent me: ‘We will always have gussets.’ So that was one of the funniest things ever.”

Cox isn't known for playing the warmest of fathers as Logan Roy in Succession, but when asked about his own daughter Margaret, Cox lights up.

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“She's extraordinary, my daughter,” Cox tells PEOPLE. “She drives me nuts. But she's also rather brilliant and she's very kind, very caring. She works as a set tutor on films and she does other stuff, as well.”

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Vertical Entertainment

Relating his relationship with Margaret to that of Max and Maxine, Cox adds: "I realized that one of the things that he wants to have is the kind of relationship that I have with my daughter that he hasn't had, that Max hasn't had with his daughter. So in a way, that's a kind of motivating force because he comes to the house and he knows he has to start again."

Related: Brian Cox Is &#39;Delighted&#39; &#39;Succession&#39; Won&#39;t &#39;Outstay&#39; Its Welcome: &#39;I&#39;m Happy It&#39;s Over&#39; After Season 4

With the recent conclusion of the fourth and final season of Succession, Cox feels fatherly towards many of his scene partners, whom he has seen grow for just under six years.

His paternal love remains especially strong for Kieran Culkin, 40, who played his son Roman in the hit series. “I have a particular strong affection for Keiran who, when he started he would get two alt lines and it would freak him out," Cox shares. "By the end of the time, he was having five pages of alt lines and his whole imagination kicked in. I just had such admiration for that kid. He is not a kid anymore… he looks like it, but he's not."

Prisoner's Daughter is in theaters June 30.

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