Long before Richard Gadd peeled back a layer of his psyche with Baby Reindeer, his Emmy-winning Netflix show, the story for his new limited series Half Man, now airing on HBO, lived in his head.

Gadd wrote the first episode back in 2019, shelving the tale of two brothers with a dysfunctional bond for four years. “But all the way through Baby Reindeer, I never stopped thinking about how much I wanted to return to it,” the writer and creator of Half Man tells Vanity Fair. “I just had the creative impulse to explore broken masculinity. If you take two men, you take them in their present as corrupted adults, and you flash back to their childhood, you contextualize all the stuff that they learned, all the prejudices that they soak up in the 1980s UK.”

Gadd gained almost 90 pounds to play adult Ruben (Stuart Campbell in flashbacks), the fractured older-brother figure of Niall (Jamie Bell as an adult; Mitchell Robertson as an adolescent), while their mothers date each other. “I like to try and change as much as I possibly can for a role,” Gadd shares on VF’s In Character video series. The Scottish multi-hyphenate slimmed down for Baby Reindeer, but sized up to be a “physically imposing presence” over Bell in Half Man. Gadd achieved his goals with the help of a nutritionist and personal trainer, but didn’t want to bulk up too much. “I always wanted Ruben to be real,” adds Gadd. “I never wanted him to have a sort of Hollywood six-pack.”

Gadd, who adopted a more “animalistic” quality to play Ruben by including “a lot of grunting” in his vocal performance, also found it important to oscillate between his character’s more charming and troubling qualities. “The show kind of sets out to explore why are men drawn to each other in such complicated and mutually empowering, yet mutually destructive ways,” he says. “I thought, ‘Well, for something to be toxic, it has to be intoxicating first.’”