Kieran Culkin annoys Succession co-star Brian Cox with ability to learn lines 'incredibly fast'

Kieran Culkin infuriates Brian Cox with the "incredibly fast" way he learns lines for Succession.

During an appearance on The Late Show with Stephen Colbert on Wednesday night, the actor, who plays Roman Roy in the hit HBO show, explained that the main skill he learned as a child appearing in commercials was being able to pick up dialogue very quickly.

However, Kieran revealed that Brian, who plays his onscreen father Logan Roy, isn't so impressed by his "party trick".

"I learn lines incredibly fast now because I've just been doing it since I was six," he explained. "It's almost like a fun party trick. It p**sed off Brian Cox one day. He has been acting for a very long time and he has a process and it takes him a long time to learn lines."

Kieran went on to recall how he arrived on set one day and realised he wasn't prepared for the scene.

"I showed up and said, 'We're doing this scene? I don't know it.' I did a quick rehearsal, and I had to go get dressed, get ready. And Brian wanted to run the lines and I said, 'F**k, I still haven't looked on it.' We got halfway through and called to set and I dropped it and he said, 'Do you know it?' And I said, 'I dunno, we'll see,'" the 39-year-old remembered. "And it just came out. I did it. He said, 'When did you learn that, just now?' And I said, 'Yes, just now.' And he said, 'Damn it!' He was so mad. (He said), 'I was up all night learning it!'"

Succession, which also stars Jeremy Strong, Sarah Snook, and Nicholas Braun, was recently renewed for a fourth season.