It makes for a pretty awkward picture: one of Hollywood's most respected directors and one of its hottest rising stars fumbling around like amateurs. The reason? Sex - and plenty of it. The star in question is Aussie Chris Hemsworth, who stars as race ace and notorious pants man James Hunt in Ron Howard's acclaimed new Formula One biopic, Rush.
The hard-living, larger-than-life Hunt, who died of a heart attack in 1993 aged 45, reportedly bedded more than 5000 women, so any accurate portrait of his life needed to reflect his feats between the sheets as much as his prowess on the track. Trouble was, neither Hemsworth, nor veteran Howard - despite more than 35 years of movie-making - had done anything quite like it before."
I remember Ron saying to me that he had never shot a sex scene like this before so he was going to let me guide him through it," says Hemsworth with a rueful laugh. "I had to tell him that I had never done something like this on a set either. So we were both there with our head in our hands going 'OK - how do we do this?'
"They are more intimidating than the driving scenes - there are 100 people around and cameras and lights and you have to get your kit off and act natural. So you have to choreograph them like anything else - it's incredibly unromantic but it's the only way to approach it.
"That Hemsworth was willing to bare his behind (he draws the line at going full frontal) and bed a bevy of beauties is testament to just how much he wanted the role. After blazing on to the world stage playing the caped, hammer-throwing Norse god Thor in the 2011 comic book movie adaptation of the same name, and cementing his position as the burly hunter in Snow White and the Huntsman, Hemsworth was searching for acting challenges beyond effects-driven action blockbusters.
Although Rush is set in the F1 world and features high-octane, authentically recreated racing scenes, it is at its heart a study of the rivalry between two contrasting drivers: Hemsworth's instinctive playboy Hunt and the clinical, methodical Niki Lauda, played by German actor Daniel Bruhl.
Although impressed by the charm Hemsworth had shown in Thor, Howard freely admits he had his doubts as to whether the towering, impossibly good looking surfer boy had the necessary range to capture the darker, more tortured aspects of the Hunt psyche. He was won over by Hemsworth's self-made audition tape, so much so that the pair will reteam next year in the period piece called In the Heart Of the Sea.
Unlike Bruhl, who was able to spend time with Lauda, Hemsworth had to rely on old footage, biographies and those who knew Hunt to find out what made the British driver tick. Beyond "the playboy, the rock star and the charismatic rebel" Hemsworth found vulnerability, insecurity and frustration, all of which fuelled Hunt's gargantuan appetite for booze, drugs and women.
"Talking to or reading about people who engaged in any sort of high-risk, adrenalin-driven activities, you become addicted to that level of adrenalin and the immediacy that sort of fear gives you," he says. "It forces you to smash into the present and they then chase that in other outlets in life. How do I find that elsewhere? The party, the drugs, the women, what else? They burn the candle at both ends and that's when you get the flip side to that.
"Hemsworth, by contrast, had a well-adjusted, outdoorsy upbringing riding motorbikes in Melbourne, dodging crocs and buffaloes in a remote Outback community, surfing at Phillip Island. The 30-year-old middle child has a fiercely competitive streak born of scrapping with older brother Luke, 32, who led the charge into acting, and 23-year-old Liam, of Hunger Games fame and, until recently, Miley Cyrus's other half.
Proud of and grateful for his close-knit family, Chris says the best advice he ever got from his parents, English teacher Leonie and social worker Craig, was: "Just have fun".
"That's what this character's motto was," Hemsworth says of Hunt. "At the end of the film the message is that no matter how many medals or cups you have, if you are not having fun then what's the point?"
Hemsworth admits he took that advice to heart when he first achieved local stardom thanks to his three-year stint on long-running soapie Home & Away. Young, single and living in Sydney he made the most of his fame - but also saw its limitations, dark side and cautionary tales.
"You have all these extremes and highs and parties and all the temptations and part of you gets swept up saying 'isn't this fun?' But at times it can be kind of lonely as well. There are plenty of tales of people who went further into it than I did.
"Hemsworth moved to Los Angeles and after initially making a splash as Captain Kirk's father in JJ Abrams' Star Trek reboot, he endured a long, lean spell and was on the brink of giving up before landing Thor. The movie was a hit, making more than $450 million. He reprised the role in last year's ensemble superhero movie The Avengers, which took more than $1.6 billion, and he will don the red cape again later this month in the sequel The Dark World.
He was a star all over again - and on a much bigger stage - but this time he says he was ready for it. Not only was he determined to make the most of the opportunities finally coming his way, he had also met his now wife, Spanish model and actor Elsa Pataky in 2010. They married less than a year later and their daughter, India, was born in May last year.
"I met my wife and there was no question in my mind that I wasn't going to find anything better out there," Hemsworth says. "We had something very special and that solved that dilemma for me. But I could certainly see how it could go in other directions if you didn't have that solid base or foundation to keep you anchored."
Hemsworth says fatherhood and his family have helped keep him in check during the wild ride of his past few years, particularly Liam who achieved stardom around the same time when Hunger Games became a huge hit early last year.
"The two of us started going through this at the same time and if there is someone who has had a similar experience - especially if it's your brother - then that's a real bonus," he says.
"You can also call each other's bluff a bit. If one starts to drift off in the wrong direction then you don't need to say 'I don't know what you are talking about' because I understand that as well. We have both been through it. There is a way of staying grounded - it's all about your friends and family and we have been lucky to have had that."