Director Taika Waititi and Chris Hemsworth on the set of Thor: Ragnarok. Credit:Jasin Boland While Hemsworth is so exhausted by the heat that he will shortly collapse onto a mat and lie quietly for 10 minutes, right now he smiles and gets ready for another take. It's a snapshot of the constant banter between the Australian star of the Thor movies and New Zealand director Taika Waititi, who has gone from the Oscar-nominated short Two Cars, One Night (2004) to success with the comic charmer Boy (2010), the vampire mockumentary What We Do in the Shadows (2014) and the warm-hearted Hunt for the Wilderpeople (2014). It will be no surprise for anyone who knows Waititi's films, his comedy appearances with Flight of the Conchords' Jemaine Clement, his famous Lord of the Rings safety video for Air New Zealand or the recent "support racism" video he fronted after being named New Zealander of the Year ("you don't have to be a full-on racist; just being a tiny bit racist is enough") that he wanted to make the third Thor movie a comedy. Just how much of a comedy is apparent when this scene appears in a high-voltage trailer that has made Thor: Ragnarok one of the year's most anticipated Hollywood movies. In a gladiatorial arena, Thor, watching from the stands, sees the Hulk emerge ready for combat. "Yessss!" he says to an eccentric planetary ruler played by Jeff Goldblum. "We know each other. He's a friend from work."

Friends from work: Chris Hemsworth as Thor and Mark Ruffalo as the Hulk in Thor: Ragnarok. Executive producer Brad Winderbaum calls this movie a "wacky space race adventure kind of buddy movie through the cosmos". Thor, after being imprisoned on the planet Sakaar without his hammer and battling his friend from work, has to speed across the universe to stop Ragnarok – the Norse version of the apocalypse – in Asgard. The threat comes from Hela, Cate Blanchett in a striking sleek outfit and antlers – the first female villain in the so-called Marvel Cinema Universe that includes the Spider-Man, Iron Man, Captain America, Ant-Man, Hulk, Deadpool, Guardians of the Galaxy, X-Men, Avengers and Fantastic Four movies. Naturally funny: Chris Hemsworth as Thor. Credit:Jasin Boland A colourful and clearly popular presence on set, the dapper Waititi is wearing a stylish light-coloured suit and flat cap. While he takes a hands-on approach – at one stage sitting on the studio floor holding a giant green hand for a shot that has the Hulk punching Thor backwards – he casually directs another scene from a beanbag. Then he retires to a chaise longue opposite a table topped with a bare cake stand.

During a break, the actor, writer, director and comic says his pitch to Marvel executives relied on the fact he knew Hemsworth was naturally funny. Mark Ruffalo as the Hulk. There's no point calling the movie Thor if he's not the coolest thing in it. Taika Waititi "I don't think they'd exploited that enough, not only in the Thor films or the Avenger films but in any of the other films he's been in," Waititi says. "He's a real comic talent and I felt like that was something that needed to be showcased." Waititi also pushed the idea that the God of Thunder, like '80s movie heroes played by Bruce Willis, Harrison Ford and Kurt Russell, should have great jokes.

The villainous Hela (Cate Blanchett). Credit:Marvel "I wanted people to be more on the side of Thor, make Thor the most interesting character in the film," he says. "There's no point calling the movie Thor if he's not the coolest thing in it." While initially not confident that Marvel would go for his approach – the directors of Gangster Squad, Dodgeball and Goosebumps were reportedly pitching as well – Waititi wanted to make the type of film he enjoys watching. He considers it the most "out there" movie that Marvel has made so far. "My approach was sort of destroying the characters from how they'd been built previously and rebirthing them," Taika Waititi says. Credit:Jeff Vespa "There are some very bad movies being made in Hollywood and some very bad movies that cost a lot of money," he says. "As an audience member who happens to make movies, I'd already formed opinions before pitching about how those films should be made, what elements they needed and what things people switch off from. Story is the main thing – making sure there is a story that is actually understandable, which seems to be the last thing a lot of Hollywood films focus on."

Waititi likes to keep the set relaxed. "The way I work with the actors, the way I work with Chris, is very similar to how I work with everyone else in my other films," he says. "You just have to create friendship and a good relaxed environment. We usually play music. There are a lot of kids around all the time – my kids and Chris' kids and everyone else's – and families are invited here. That's the key to making the job enjoyable." Whatever the budget is after generous subsidies from the federal and Queensland government to attract the production, there is no doubt Thor: Ragnarok is a big Hollywood movie. It occupied all nine sound stages at Village Roadshow Studios, plus the outdoor construction of what is called the Asgard Piazza, with 1500 cast and crew on the biggest shooting day. It's such a high-security operation that visiting journalists, as well as signing a waiver to stop details getting out, are given Marvel S.H.I.E.L.D stickers to place over their phone cameras. For Hemsworth, Waititi's approach feels like a fresh start for Thor. "When his name came up in amongst a bunch of people, it was the one I was screaming about," he says. "Boy is one of my favourite films. And this was even before Hunt for the Wilderpeople, which I love equally as much. So he had my vote but there were a few votes that were needed to make that decision." There was a feeling – shared by Hemsworth and Waititi – that it was time to break away from the Old English and the Shakespearean aspect of the earlier movies, especially since the God of Thunder had lived on earth for two years since his last screen appearance in The Avengers: Age of Ultron (2015).

"As soon as we got on the phone, we both talked about things we disliked about what I'd done before," Hemsworth says. "We were saying, 'I get sick of this sort of thing' and laughing and going, 'good, any time we feel it's heading in that direction, just do the opposite'."Winderbaum, who has also worked on Ant-Man and Iron Man 3, says Marvel executives loved that Waititi wanted to make use of Hemsworth's sense of humour, which has also been showcased as a Texas weatherman in Vacation (2015) and a dim office assistant in Ghostbusters (2016). "Chris is seen as a handsome, super-buffed leading man so it's always really surprising when he's getting the biggest laugh," he says. "Whether it's Ghostbusters or Age of Ultron, he's winning scenes all the time. It was something that Taika appreciated from the very beginning. "The other thing he brought to the table was a driving energy to Thor that is very prevalent in the comic books but that we've never really captured on screen before – this all-out, balls-to-the-wall epic space adventure that just grabs you by your collar and yanks you on this journey and doesn't let you go. He made a pitch reel that was cut together from other films that just blew our minds." Even on a Hollywood blockbuster, Winderbaum hopes Thor: Ragnarok has the same warm-hearted comic style as Waititi's other films. "I hope, if we do our jobs right, that this film won't just fit into the Marvel cinematic canon, which is known for multiple genres and multiple tones all living together, but will fit into the Taika Waititi canon," he says. "He has a real talent for not just comedy but also gravity and creating movies that have three-dimensional characters that you feel for and can be really funny in different situations but feel like a real world with real stakes."

For his part, Waititi says he found Marvel was open to directors with unique voices and a vision, with James Gunn on the Guardians of the Galaxy movies and Scott Derrickson on Doctor Strange two other examples. "I made sure I was very vocal from the beginning – saying 'I think it should be like this' and 'I think it should be like this' and they kept agreeing," he says. "The way I've been looking at Ragnarok, which is the idea of the end of the world – the cycle – is that it's also a rebirth. "My approach was sort of destroying the characters from how they'd been built previously and rebirthing them, making them more interesting. In a way, treating this as the first Thor film. Not to take away anything from those films but I didn't want to come into this and make an episode of something or the 'third film'." Waititi set up the new movie by releasing two jokey videos about Thor spending some "me time" and bonding with his gormless Australian flatmate Darryl while the Avengers were battling each other in Captain America: Civil War (2016). "There's definitely a lot of new stuff with him," he says. "You'll still recognise him – he's like a polite rich kid from outer space. But he's more weathered. He's travelled a lot more. Had more life experiences." On his own new life experience - making a superhero movie - Waititi has enjoyed the huge step up from smaller films, with the main differences being the number of people and the level of talent.

"The machine is a lot bigger and moving that machine around takes a lot longer," he says. "So it's more of an expansion of scale and the time it takes to shoot stuff. "It's a lot slower than what I'm used to because there are six or seven times more people involved and all this gear. I don't usually have a plush red sofa on my sets but it was just there from another film so I can, 'can I have that?' And perks. You get treated very well." After Thor, Waititi has plans for both big and small films. One is for a sequel to What We Do in the Shadows, focusing on the the werewolves who were memorable side characters. Another is an animated film, Bubbles, about Michael Jackson's life from the perspective of his chimpanzee. But he has a firm view on what it would take for him to direct another Hollywood blockbuster. "This has been such a great experience but really it would depend on the content and also the people that I worked with," he says. "You hear so many bad stories about people's experiences on big films. Not every actor out there, especially celebrity actors, are as nice and accommodating. There's definitely a lot of egos out there that I'm not very interested in working with."

Thor: Ragnarok opens on October 26.