Richard Gadd never planned to play the “unhinged” Ruben Pallister in his new BBC and HBO series Half Man.

During a talk at the Canneseries festival this week, the Baby Reindeer creator revealed it was Jamie Bell, who plays his co-lead Niall Kennedy, who had the idea when they met in L.A. to discuss the show.

“Jamie was the first person to bring it up,” he recalled. “He said, ‘I really want to be acting opposite to you in this… Have you considered being Ruben?’ Nobody had ever suggested it before. I thought if I was in it I’d be a police man or have a cameo as a bar tender.”

Around the same time, HBO and the BBC began encouraging him to appear in his new show following the unexpected global success of Netflix drama Baby Reindeer, in which Gadd starred as comedian Donnie Dunne stalked by a woman, Martha.

“The only meaningful character and large left at that point was adult Ruben,” he continued. “It terrified me – you don’t look at Donnie Dunne and think, ‘That’s Ruben Pallister’, this epitome of masculine id. I went home and said I’d think about it. I was very shaken by the idea. Acting is a very vulnerable thing.

However, after sleeping on it, he realized fear was “not good enough” an excuse to turn down the part. “A role like this so far from me doesn’t come around so often,” he added. “I would be depriving myself of that by worrying what people think about me. I woke up the next morning and said I would do it.”

Gadd began writing Half Man in 2019 prior to Baby Reindeer being greenlit, but left it on the shelf to focus on his Netflix show. The story is about two very different and extremely close men who grow up as brothers due to their mothers’ relationship. They are brought back together when Ruben gatecrashes Niall’s wedding, and the series jumps back and forth between the present and the past, with Stuart Campbell and Mitchell Robertson playing them as teenagers.

Once confirmed in the role, Gadd went about a physical transformation to highlight the size difference between Ruben and Niall, and the power dynamic between them.

“He needed to be unhinged,” said Gadd during the chat at the Palais des Festivals. “Burly was the word I kept using to the personal trainers and nutritionist – I didn’t want one of those Hollywood bodies. To me, he wasn’t a gym goer. His body was heavy because of life, and experience is weighted within him. It’s almost animalistic and it had to be real – I wanted him to be a force of nature visually. I felt I needed to tower over Jamie to be the epitome of masculine violence.”

The series, from Banijay-owned Mam Tor Productions and Thistledown Pictures, launched on HBO last night and debuts today on the BBC iPlayer, before a broadcast next Tuesday (April 28).

Gadd was in Cannes to receive the Canneseries Prix Konbini de L’Engagement honor. Besides Half Man, the meaning behind which he said would remain ambiguous and open to interpretation, the Scottish writer-performer recalled how he went from a comedian playing at the Edinburgh Fringe Festival to an overnight global star. Though the show didn’t immediately explode when it launched in 2024, word of mouth quickly gained momentum.

“The show came out on Thursday and nothing much happened,” he said. “My manager took me to a restaurant. I realized it was a ‘better luck next time’ meal, and then the weekend came, when people do all their binging and by Sunday I couldn’t go anywhere. I was always an off-beat writer doing Fringe shows in the backs of pubs and then all of a sudden I’m stratospherically famous. It is a crazy thing to go through.”

The series, based on his autobiographical one-man show, saw him play Dunne, an aspiring comedian working in a London pub who is stalked by a Scottish woman he first meets crying in his bar, and dealt with male sexual violence in later episodes.

Asked about why the show cut through, Gadd responded: “If you look about the two shows of the past three or so years that have exploded into public consciousness and zeitgeist, you think of Baby Reindeer and Adolescence. One was about a comedian’s psycho-sexual relationship with his stalker and the other was about a 15-year-old killing his female schoolmate. None of them scream commercial hit. They hit the landscape with overriding authenticity. All you need is authenticity to have the trappings of a hit.”

In essence, this formula could be applied to many of the most influential TV shows of all time, he added. “If you look at all of the success stories in television are ingenious ideas told through the prism of a singular voice… Stories you didn’t realize needed to be heard: The mob boss with clinical depression, the chemistry teacher cooking meth, the sex addict and a priest falling in love. That is the kind of story that captures the zeitgeist.”

The show, from Clerkenwell Films, went on to win six Primetime Emmys, two Golden Globes, a BAFTA, a SAG Award and a TCA Award.

Both Gadd and Jessica Gunning, who played Martha, were feted for their roles, and he revealed an interesting aside on the casting process. “We saw a lot of people for Martha,” he said. “It was a much sought after role and it hit the Atlantic as well: People in L.A. and Hollywood were desperate to get involved.

“I can’t say who they are, but you wouldn’t believe the famous actresses who wanted to play that role. It was a gift – We were seeing anyone between 45 and 55, and people really wanted it, but I never wanted the Hollywood side to it.

“I thought it would ruin the story having fame right the center of this idiosyncratic London story, so I resisted it and resisted it. Jess was the only one to play the cuteness. A lot of people played the crazy, but she played the cuteness and I fell in love with her right away.”

In a charming aside, Gadd noted the numerous times his new-found fame had surprised him. “I remember seeing Steve Martin and asking for a photo and him asking for one back,” he said laughing. “I grew up a big WWE wrestling fan and a big John Cena fan, and I got a video on my phone one day from John Cena telling me how much he loved the show.

“Elton John phoned me and I was so moved by that, but the biggest one was The Pogues. Shane [MacGowan] sadly passed during the sound mix of Reindeer, but I met the rest of the Pogues and I now have all their numbers, and they being be backstage at gigs.”