Having made his name in the horror genre, at first glimpse James Wan may seem an unlikely choice to helm a big budget comic book movie.

But having directed The Rock and Vin Diesel, the Aussie director notes that “Jason is easy compared to those guys.”

Wan grew up on a diet of George Lucas, Steven Spielberg and James Cameron films, and says that his goal has always been to make those kind of movies.

“Horror is definitely the best way to break into the industry but I became synonymous with it, so people had a harder time seeing me for anything else,” he says.

“But I wanted to prove that I’m not just a horror filmmaker. I’m a filmmaker, period.”

When he was offered Aquaman, however, he was somewhat underwhelmed. “Let’s face it. He’s the superhero that everyone makes fun of,” he grins. “But the more I thought about it, I realised how I’ve always loved being the underdog. Coming from the horror genre, you’re always the underdog; the bastard stepchild that no one respects. So I thought: What if I’m the one who gets to make Aquaman super cool? How awesome would that be? And with Jason as well, it takes it to a whole different level.”

The director gives his horror partner-in-crime, Leigh Whannell, a cameo as a pilot in Aquaman, also casting Dolph Lundgren as Nereus, king of the Atlantean tribe Xebel; Yahya Abdul-Mateen II as the vengeful Black Manta; and Patrick Wilson as Orm/Ocean Master, the present king of Atlantis.

Wan’s angle was simple. “It’s a classic hero’s journey. He begins as a reluctant hero but then he goes on this journey to become the hero that he’s supposed to be, just like the boy Luke Skywalker becoming the man.”

Pitching it as somewhere between Star Wars and Lord of the Rings but underwater, his only caveat was monsters.

“I told them, ‘I hope you guys are OK with monsters in there. I’ve gotta have monsters!'”

Aquaman is in cinemas Boxing Day.

Read our interview with stars Jason Momoa and Amber Heard