Richard Madden only looks 19; he’s actually 32. Still, it’s a little surprising to hear him describe the distance between his run as Winterfell scion Robb Stark on “Game of Thrones” to David Budd on “Bodyguard” as “moving on from being a son to being a father.”

“I’ve played Romeo twice on stage,” the handsome Scot says in a lilting brogue, “but I’ve kind of played incarnations of Romeo for the past 10 years in all my parts. So to move on to someone I really don’t see as a Romeo character, I’ve loved doing that.”

Sunny, smiling and lighter-haired than “GoT” fans will remember him, he allows that it’s still a bit of a whirlwind — “Bodyguard’s” rating success (setting viewing records in the U.K.) and honors (Golden Globe and Critics’ Choice nominations for him). His ex-soldier, now policeman assigned to protect the U.K. home secretary is indeed a young father, though that might not be the first quality that comes to viewers’ minds. Budd is a PTSD sufferer who experiences triggered rages and near-panic attacks. In moments of action, he’s at his best.

“If he’s saving someone else, it keeps him intact,” says Madden. “He can fix that. For a man who’s been through such trauma in his life to go straight back into a job like that, it’s repeating cycles.

“But that’s his purpose in life. When he stops doing that, he feels completely redundant. And all these other things he’s been pushing back start creeping up on him.”

And that’s where the father-and-husband thing comes into play. Budd is, in his professional guise, stoic, efficient. But underneath that are roiling waves that lead to some unprofessional behavior and outbursts that make it understandable why his wife wanted out of their marriage.

“That’s another thing about this, to not be scared of being disliked. Particularly in the scenes with my wife. Those scenes on the phone, there’s a certain — ” he takes on an aggressive harshness, “tone that I speak to her in that is horrible. It’s a way of speaking to someone that people will very much dislike. And I dive straight in because I thought it was important to understand. But then, when we see them alone, how much she means to him is conveyed, and that all ties into his PTSD.”

Budd and the show probably confound American audiences. He barely fights; many characters live in a gray zone between good and bad. It expresses some unusual points of view for a thriller, such as veterans voicing anger with the politicians who sent them to war. And Budd’s ultimate triumph may be that he stops denying he needs help.

“I read a statistic that 13 years is the average time it takes from someone having a traumatic experience to seeking help for PTSD. That’s a huge amount of time. And it festers and grows, and it can dominate your life and you don’t even know it,” says Madden.

“A friend told me, ‘You put “PTSD” in your CV and you’re not getting the job.’ He says there’s shame and stigma involved with it.”

Madden already has 25 screen credits but allows that “Bodyguard” put him through his paces like no other project so far.

“Emotionally and physically, it took it out of me — that whole last scene,” he says of an almost entire-episode-spanning standoff to close the season, “we shot in minus temperatures in London, and I’m just in a shirt and a [vest].

“Mentally, it did take it out of me. It’s not a comedy. It’s a relentless …show, really. And you’re dealing with a very damaged, broken man.”

After a shocking occurrence in the twisty series, David is shaken to his core. A moment that probably shocks audiences even more finds him attempting suicide as a result.

“Doing that scene — killing myself — you have to get to a certain point, a certain understanding that David gets to, where he thinks him not being there will be better for the world. It’s a strange place to bring yourself to. You’re not laughing and joking between takes. The whole job was very much that.

“You come home at night … you’re carrying something that I can’t just switch off, because the very next morning I’m straight back into that place. You kind of go into standby mode until the next morning. Five months of that takes its toll.”

But it’s the aftermath of the attempt that Madden feels shows you who Budd is:

“He’s with his children. That’s really defining for him, and for me as an actor, playing a father, not a son anymore. He’s always trying to be so strong for people, and he’s so ashamed of himself at that moment. He just wants a cuddle from his children, how powerful that is ….

“That’s the character I fell in love with; that man who’s starting to accept there’s something wrong with him and he needs help.”

Interviews From 2018