It takes five and a half hours, three lattes (two with sugar) and one Academy Award-winning actor to record an audiobook. When that audiobook is Fantastic Beasts and Where to Find Them, that is.

Eddie Redmayne arrives at Audible HQ to narrate the brand-new edition of the Hogwarts Library book Fantastic Beasts and Where to Find Them, on a bitter winter morning in London. He’s ready to become eccentric Magizoologist Newt Scamander again. Ready to reprise the role he played in the movie Fantastic Beasts and Where to Find Them. Only this time, he’ll have to do it using only his voice.

Eddie greets me with a bear hug, strides into the recording studio and takes his place in front of the microphones. He reaches for the A3 version of the book in front of him and flips it open to the foreword – a new one, written in Newt Scamander’s inimitable voice.

As the sound engineer and director make sure the sound levels are right, Eddie whispers something under his breath and shakes his head and shoulders a little, as though he’s trying to physically transform. There’s only one sentence Eddie Redmayne could have uttered in that moment, he tells me later.

‘I haven’t done many voice recordings before, so when I was trying to get back into Newt’s skin – when doing the reading of Fantastic Beasts and Where to Find Them – I kind of used the same technique that I did on set,’ he says with a conspiratorial grin. ‘There was one line in the original script of the film, in which Newt says: “I’m not sure that anything that occurs in nature can be unnatural.” The line ended up not being in the film but I always used it as my way of re-finding Newt’s voice. That was my way to get back into his skin today.’

His favourite sentence spoken, Eddie starts to read as Newt. I watch as he hunches his shoulders slightly, as though he’s trying to make himself shorter. He’s doing Newt’s body language as he speaks; he can’t help it.

‘I did find myself starting to cower over in that way that Newt does,’ he tells me afterwards. ‘He’s not particularly good at eye contact as well and, hilariously, in the recording booth they have this big face which is meant to be the person that you as a recording artist are speaking to, so I sort of found myself refusing to make eye contact with it, which was quite entertaining.’

As you know, the book is laid out like an encyclopaedia of magical beasts, organised in alphabetical order. Once he’s read the new foreword (which is fantastic, by the way, and crammed with exciting details), Eddie gets to the first entry in the textbook: A for Acromantula. By the time we get to the letter B, Eddie pushes aside his stool and stands tall and proud.

He interrupts himself several times to say things like ‘Oh, she’s good, isn’t she!’ about one of J.K. Rowling’s sentences in particular, or ‘Is it still sounding Newty?’ He seems, as he’s reading, to be astonished and enchanted by the book all over again. He flips between Eddie the Harry Potter fan and Eddie the actor we all know. It’s quite lovely to watch.

‘Before I got cast in the film, and before I’d even read the script, David Yates had told me about Newt and about this textbook. It was obviously the first thing I read in relation to the film,’ he says. ‘I just found it so funny and enchanting and I found it really wittily written. Until you start reading it out loud, you forget how brilliant J.K. Rowling’s use of the sounds of language is. There’s a lot of onomatopoeia and really tongue-twistery words. Occasionally I had to stop just because I was incapable of saying the words without either laughing or getting my tongue in a muddle. It was wonderful. It’s just such a beautiful book.’

That’s true. Eddie does stop a few times, with some of the more complicated entries. Which is entirely understandable — just you try and say ‘An offering of woodlice will placate the Bowtruckle long enough to let a witch or wizard remove wand-wood from its tree’ in one take. There are some descriptions that seem to particularly tickle Eddie’s sense of humour. When he reads the line ‘Augurey feathers are useless as quills because they repel ink,’ he stops, rolls his eyes, puts his hands in the air and says, ‘I’d forgotten how good this book is!’

Eighty-eight pages and six brand-new beasts later, Eddie Redmayne remembers exactly how good the book is. And it’s more exciting than ever, narrated by Newt Scamander himself.

The digital audiobook of the Hogwarts Library book Fantastic Beasts and Where to Find Them narrated by Eddie Redmayne, is available to buy now from the Pottermore Shop.