Actor Jeremy Strong, who plays Succession’s Kendall Roy, came out of filming the family dynasty smash-hit’s first season afraid that audiences would see the show as funny. In a new profile in The New Yorker, castmate Kieran Culkin, who plays Kendall’s brother Roman, remembered Strong coming up to him after they’d wrapped. “He said something to me like, ‘I’m worried that people might think that the show is a comedy.’ And I said, ‘I think the show is a comedy.’ He thought I was kidding.”

The profile’s writer, Michael Schulman, described Strong in a Saturday tweet as “one of the most intense people I have ever met in my life.” Showrunner Adam McKay told Schulman, “That’s exactly why we cast Jeremy in that role. Because he’s not playing it like a comedy. He’s playing it like he’s Hamlet.”

Strong’s process is reportedly so intense and isolating—though he shies from the label of ‘Method acting,’ a notoriously fierce technique where actors more or less try to become their characters—that fellow Succession star Brian Cox expressed concern. “I just worry about what he does to himself,” Cox, who plays family patriarch Logan Roy. “I worry about the crises he puts himself through in order to prepare.”