Maybe it’s what he wants me to think, but at first blush Tom Hiddleston seems nothing like Loki.

For one thing, he’s just too damn nice: without his lank, black wig, lurid green cloak and golden helmet he’s just an unusually good-looking fellow, in a tidy casual suit and sporting stubble and short, sandy brown hair, welcoming me into a hotel suite overlooking Sydney harbour (“And honestly, what a view – and you get to live with it?”).

For another, Loki would definitely not have missed out on the opportunity to deck star Chris Hemsworth at some point during the filming of Thor: The Dark World, the forthcoming entry in Marvel’s sprawling superhero franchise and sequel to 2011’s Thor.

“The thing is, it wouldn’t be fair anyway because every time he’s hit me, I’ve asked him to. Because I’m insane.”

It’d be payback, though – after all, Tom legendarily got a pasting from Chris during the filming of The Avengers.

“What it was that Chris and I were filming the Thor-Loki fight on Stark Tower and Joss [Whedon, Avengers writer-director] came up after a few takes and said ‘It just doesn’t look like you’re hitting him that hard,’ and Chris said ‘Well, I’m not.’ And I was wearing that big helmet, so I said ‘look, I’m protected, just go for it.’”

And it worked? “Well, it begins with that moment when he piledrives into my chest,” he smiles. “It only took one take after that. Which was good – I don’t think I could have taken more.”

He pauses. “It was so funny, though: he did it and I went down – like, straight down – and Joss called cut and immediately turned to Mitch Dubin, the camera operator, and said ‘Mitch, mate, you saw him, you heard him tell me to do that’ and he was like ‘Oh yeah, I saw, Tom brought it on himself…’” He chuckles to himself. “Good times.”

The filming of The Dark World wasn’t any easier, it seems. “There was one point where Loi takes a hit and I had to fall back on the surface of a volcano – we’ve all been there – and there was no mat and no padding, and I just ran up to the mark and did a sort of Fosbury Flop, like a high jumper, onto the hard, rocky surface of an Icelandic volcano.”

It’s a glamorous business, this acting lark. “Oh, it is! It’s fun, though. I do enjoy it.”

Of course, most of the filming didn’t involve falling onto volcanos – or, indeed, anything at all. In fact, most of the sets and props used in the film exist only inside the design team’s computers, which must provide a challenge for someone who grew up on the rather more physically tangible environment of the British stage.

“Indeed. But when I was in drama school we had this amazing class in mime. The teacher was a very, very playful person. He’d ban notepads from the room – he’s say ‘write down what you want to forget, this is not about taking notes, this is about your imagination’ – and he’d make us do stuff, just like you’d see on Paris pavements. You know, with clowns pretending that it’s raining and then they’re walking down the street and taking their umbrella and shivering. And green screen is really no different: it’s about building the fiction of what you’re responding to in your imagination.

“So there’s this whole scene where Chris, Natalie [Portman] and I are in a spaceship and Thor, Loki and Jane have to get somewhere very urgently, and the set we’re actually in is just this grey shape, absolutely stationary just outside the M25 in London. We are not actually sailing through space between the stars of Asgard…”

Hold on: so this wasn’t filmed on location?

“I hate to break it to you, man: we were not actually up there in the Nine Realms. Is the illusion coming crashing down?”

Give me a minute. This is a shock.

“It feels like The Wizard of Oz, doesn’t it? You’ve just seen behind the curtain.”

Next you’ll be saying The Wizard of Oz wasn’t filmed on location.

“Oh god.” His hand goes to his mouth, his eyes well with false sincerity. “I’m so, so sorry. Do you need a moment?”

Actually, maybe he is Loki after all.