The Assassin's Keeley Hawes and Freddie Highmore reveal their unusual on-set "addiction"

A form of extreme bonding, if you will...

And it's not just Julie and Edward who share a great deal of affection for one another –beneath the many layers of exasperation, and in spite of the many misdirections and lies.

Hawes and Highmore (now there's a detective series waiting to happen), who had never met prior to working together on The Assassin, quickly formed a strong camaraderie, both on set and off, which was partly powered by their shared love of one thing in particular.

"We were both quite, addicted is too strong a word, but in the heat of Greece and in Athens, we would have a lot of Coca-Cola every day," said Highmore.

He then asked Hawes if she has kept up her "addiction", to which she said that she had, while Highmore, by contrast, had "given it up a bit".

But he joked that being in his co-star's presence was "bringing back the desire" for a full fat red Coke.

You can enjoy that conversation with Radio Times in the video at the top of this page.

And it's a good job the pair got on like a house on fire because the Williams brothers' script demands a lot.

"We'd wanted to write a mother-son dynamic for a while, it seemed funny and interesting that they’re estranged," said writer Jack Williams.

"It's not something you see a lot of in drama, or if you do, it's all very tortured and very straight-laced. As a sort of central pairing, it didn't seem like we'd seen many shows with this kind of tone that had that at the heart of it."

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His co-writer and brother, Harry, added: "Yeah, normally the emotionally cut-off parent would be a dad, wouldn't it? It’s rarely a mum and the son.

"So that felt instantly like an interesting thing, and then having that kind of Private Lives-y, back and forward dialogue, being horrible to someone, but also those two people really love each other was hugely appealing to us.

"Because it just has huge potential for comedy, and people who are mean to each other is always funny."

Alongside Hawes and Highmore, the rest of the cast includes Shalom Brune-Franklin, Devon Terrell, Gina Gershon, Jack Davenport and Alan Dale.

The Assassin streams on Prime Video – you can sign up now for a free 30-day Prime Video trial.

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