One of the stars of Outlander: Blood of My Blood has revealed details about their latest film project beyond the Starz historical drama, reports the Daily Record.

Peter Mullan, recognised by Outlander enthusiasts as Red Jacob MacKenzie, features in the touching biographical picture I Swear, which chronicles the life and dedicated efforts of activist John Davidson in raising global awareness about Tourette’s syndrome.

In an exclusive conversation with Reach Screen Time regarding how I Swear differed from his more substantial budget productions, Mullan explained: “When you’re in those bigger projects, the level of nervousness is different.

“You walk on the big set, the Harry Potter set, the Blood of My Blood set, Dept. Q, your first thought is: how do I fill this? How do I justify the wage I’m getting and this big set that people have spent tonnes of time on and possibly millions of pounds building?”.

“So you spend the first couple of days just trying to feel secure that you’re okay, you’re part of this.”

He added: “A film like [I Swear], when you go down the other financial end of the strata, the pressure’s no less but it’s different. You walk in on a project like this, that sort of nagging thing’s not there. It’s more about, how do I get into it? And I hope I get along with everybody.

“Something like this, it happens very quickly and the second you feel like that, then you’re really in the playpen and you can run about as much as you like because you feel secure.”

He further explained: “And that’s the biggest difference between this and other [projects] from an acting point of view.”

His co-star, Shirley Henderson, renowned for her roles in the Harry Potter series and Netflix’s Dept. Q, also shared her thoughts on how I Swear differed from her larger projects.

She expressed: “It was a small, little budget but a beautiful little script. There was something magical and interesting and a little bit dangerous about it.

“First of all, there’s no money, it’s down there compared to something like Dept. Q, and I imagine Outlander and all the things [Mullan’s] done. So, that’s the main difference but it’s concise, it’s beautiful, it’s going to be a one-off thing.”

Henderson confessed that the cast didn’t “feel the machine” that comes with bigger projects.

I Swear chronicles the life of John (portrayed by Robert Aramayo) from his teenage years in Galashiels, Scotland when his Tourette’s tics first begin, through the challenging journey of school expulsion, family rejection, and even physical violence, before coming out on top.

Peter Mullan, known for his roles in Ozark and Westworld, plays the compassionate caretaker Tommy Trotter, who employs John at the local community centre and forms a friendship with him.

Meanwhile, Moray-born actress Henderson portrays John’s mother, who struggles to understand her son’s condition, leading to the collapse of her marriage and estrangement from her son.

Joining Aramayo, Henderson and Mullan in the cast is Shameless and Black Mirror actress Maxine Peake, who portrays Dottie Achenbach, a character who becomes a mentor to John.

I Swear provides an emotional rollercoaster from beginning to end, oscillating between heartbreak and warmth as it unfolds John’s narrative.

I SWEAR is available to buy and rent from digital platforms now and will be available to own on Blu-ray and DVD from December 29

Outlander: Blood of My Blood is streaming on Starz in the USA and on MGM+ via Prime Video in the UK