Keeley Hawes formed a mother-son bond with Freddie Highmore, her co-star in thriller The Assassin

Hawes is, of course, one of British television’s biggest names, her CV stretching from Spooks and Tipping the Velvet to Bodyguard and Miss Austen. Highmore followed a first act as a child star with bona fide US small-screen stardom in the Psycho prequel TV series Bates Motel and the medical serial The Good Doctor.

The pair play mother and son Julie and Edward, whose messy, awkward relationship is defined by emotional distance and secrecy. Julie has retired from her clandestine life as a hired killer and now lives in a hillside cottage on a remote Greek island; he is an earnest investigative journalist, meeting her for the first time in four years with some significant life news and a burning desire to identify his father (“There will be references to Mamma Mia!” Highmore laughs). Then that old “one last job” rears its head for Julie and all hell breaks loose.

“This has flown by,” says Hawes, who’s dressed in the retired assassin’s costume of vest top and three-quarter-length khaki trousers. “Getting on isn’t a given and if you’re not having fun, it can feel like a long time to be away from home.”

“We’re oddly on the same page, even more than one might think,” says Highmore, every inch the holidaying hack in crumpled shirt and jeans. “There are moments when we look at each other and think: ‘We’re sort of the same person in this weird way.’ Or certainly on the same wavelength.”

That rapport is born from a shared sense of humour and affectionate mutual teasing, which surfaces frequently. But perhaps it also comes from the shared experience of starting out in the industry at such a young age.

Hawes signed up for the Sylvia Young Theatre School at nine and worked as a model before getting her big break at 19 in Dennis Potter’s Karaoke, while Highmore – the son of an actor and a talent agent – was ten when he was acting opposite Johnny Depp, first in Finding Neverland and then in Charlie and the Chocolate Factory.

“We’ve never spoken about that,” marvels Hawes. “Isn’t that weird? Freddie looks young, but he’s wiser than his years. Maybe an element of that comes from being treated as an adult from so young, because that’s what happens on the set. But I certainly didn’t feel like I missed out on anything. I had the time of my life, but it’s a very different thing now – I imagine I’d have a tutor and so on, but the rules were more relaxed then, with all the pros and cons of that. It didn’t feel like working, just really exciting. And it still is, most of the time.”

“I always had a great time filming when I was young,” agrees Highmore, who took time out to study languages at Cambridge and work as an intern at banks and law firms. “But it’s not play – you’re aware there’s a seriousness, which for me was part of the enjoyment. Acting felt like an addition to my childhood. My parents helped me maintain a degree of separation and normality. Going to university and not acting for a bit was really important because I never wanted acting to become a continuation of my childhood rather than the choice of an adult.”

Greece has been an annual holiday destination for Hawes and her family since The Durrells finished in 2019. “It’s been lovely to be back and working with a lot of the same crew,” she says. “You feel immediately relaxed. It’s the sort of location where people want to come to visit you – my kids are old enough that they’ve all come over under their own steam.”

For Highmore, it represents a welcome change after more than a decade leading two long-running series. “There’s a part of me that misses the family you build over shows like that. At the same time, it’s really exciting to do something else, especially something British after so long in North America. Even though it’s Athens, it feels familiar.” He looks apologetic. “I’m afraid I can’t give you a pithy reason why British television is different from American, but there is an inherent difference.”

“The catering is better over there,” suggests Hawes, and Highmore chuckles heartily. The laughter will continue through the night: soon they’ll be clambering into a 4x4 to brave the mountainous hairpin bends up to a derelict military outpost. The ensuing gunfight, thrillingly staged and enthusiastically performed, isn’t a novel experience for Hawes, who has form with action scenes in BBC1’s Crossfire.

“I had a scene where Julie puts a rifle together, which I learnt to do in my trailer 20 minutes beforehand,” says Hawes. “I’m not bad at Lego so I didn’t find it too difficult. In fact, I had a note afterwards to look more inept! This is the most stunt-y show I’ve done, and we’ve been allowed to do a fair bit ourselves – I did throw a man over a car – but I feel no pressure because Julie’s meant to be rusty. Julie’s out of practice because she’s been on the hill, drinking a lot. A lot of the fights are improvised, they’re not meant to look slick, so when I screw up, I can blame it on the character.”

Even though the physicality was enjoyable for both actors, it was the emotion and nuance of the family dynamics that appealed most. “I find their relationship really relatable,” says Hawes. “I have that back-and-forth with my children, so that part feels very real to me. Quite often you do clash with the people you’re most like, probably because you recognise things in them that you don’t like in yourself. Julie does have that vulnerability beneath the surface, but she also doesn’t care about being likeable – I admire people like that.”

“There’s a tragedy at the heart of their relationship,” adds Highmore. “In some ways they know each other better than anyone else, despite the secrets they’ve been keeping from each other. They want to be closer and know they should be, but they just keep getting it wrong. They’re both alone in a way, feeling a little separate within the family structure, seeking that connection and trying to find a place in the world.”

“That’s brilliant,” says Hawes. “Can I use that when you’re not around?”

“Of course!” beams Highmore, leaning forward to whisper conspiratorially: “We haven’t spent ten years as friends before the show, but it feels like we have.”

Hawes goes still further, with a glint of mischief. “Freddie basically is my son!”

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