So you’ve seen Katherine Waterston in costume as 1920s witch Tina Goldstein and now you can’t stop thinking about that perfect green gumdrop hat she wears. Me too.

You’ve been seriously considering a curly honey-coloured bob since you saw Alison Sudol in blush-coloured silks as Queenie Goldstein. Yeah, me too.

Costume designer Colleen Atwood has dressed the Goldstein sisters – the two central American witches in the Fantastic Beasts movie – impeccably. And like all of Colleen’s costume work, the way she’s dressed the Goldstein sisters is not just about aesthetics. It’s about literally weaving elements of their character into their clothes.

First, let’s find out what Colleen was thinking when she designed Tina’s sensible, storm-coloured outfit.

‘Well,’ she says. ‘Tina had been an Auror. She’s fallen out of that world but I still wanted her to have the feeling of that world. So I gave her an overcoat that’s a little bit loose like an Auror’s coat, but made of more ordinary fabric, as though she’d downgraded from that spectacular leather silhouette of the Aurors. Right from the start, I saw her in soft, cooler colours and warm greys, those sort of tonalities.’

That lovely almost-masculine elegance is deliberate, too. And makes perfect sense as you get to know Tina’s endearing pragmatism a little better.

Queenie’s utterly different. Her whole demeanor is lighter, softer and more feminine (but don’t be fooled into thinking she’s a lightweight in any other respect). Tina and Queenie are fragile and strong, beautiful and unaware of it, smart and romantic in their own ways. There are so many clues in the costumes – and even the way each woman brandishes her wand.

‘Queenie uses her magic in a different way; she’s got a different energy to Tina altogether and I wanted to dress her in a different way, keeping her light and her colours light: air-like and rosy and warm and approachable,’ says Colleen.

As you may be able to guess by now, Tina and Queenie get caught up in the chaos that ensues when Newt Scamander’s case is opened. Katherine and Alison do a lot of chasing, running, sneaking, hiding and striding in their clothes and Colleen had to plan for that.

‘I have six of Tina’s costume and six of Queenie’s,’ says Colleen, who made duplicates of all the principal cast’s costumes to weather the adventures in the movie. ‘It would have been useless to find one real outfit for each of them from the era, they need so many of them.’

Ah, there’s so much more to tell you about Colleen’s costume strategy, Katherine and Alison’s chemistry on set and what they think of their own characters. I cannot wait for you to get to know the Goldstein sisters better. They’re smart, complicated, kind, vulnerable, funny and brave.

That is to say... They’re magical, but they’re also very real.