When film-maker Todd Phillips and actor Jonah Hill read the 2011 Rolling Stone article about two stoners who became international arms dealers, neither could believe it. Now, after teaming up to turn the tale into a movie, they tell Susan Griffin how it all came about

TODD PHILLIPS was flying to Bangkok, flicking through Rolling Stone magazine when he came across the incredible story of two audacious 20-somethings who became international arms dealers. "I couldn't believe it was real. It just blew my mind that this was a real story, and the more I looked into it, the more it started feeling like a movie," says the film-maker, who previously helmed the Hangover movies starring Bradley Cooper.

That feeling was so strong that Phillips didn't let it go, and War Dogs is the first project to come out of his and Cooper's production company.

"Ever since the first Hangover in 2009, we became best friends and we just love working together," the 45-year-old explains, puffing on an e-cigarette, of going into business with Cooper.

He is mortified to think people might see the title and presume they've made a pro-war movie.

"There have always been a lot of movies about wars and soldiers and patriotism - this is not that movie. It's really not about war, as much as it's about the obscene amount of money a small group of people make from war."

The story follows Efraim Diveroli and David Packouz, two friends who exploit a little-known government initiative during the early 2000s that allows small businesses to bid on American military contracts. Starting small, the money soon rolls in, but then they get in over their heads after landing a £300m deal to kit out the Afghan Army.

Jonah Hill - whose credits include comedy hits This Is The End and 21 and 22 Jump Street, and who was Oscar-nominated for his roles in Moneyball and The Wolf Of Wall Street - was always first choice for the role of the outlandish Diveroli.

"We wrote the movie with Jonah in mind," reveals Phillips. "He is electric when he's on screen. That, and also he's jumped between drama and comedy so seamlessly, that he really helped us tonally identify this movie."

Hill didn't have any contact with the real Diveroli ahead of production. "I've played real people a handful of times, and sometimes they're really psyched about it, sometimes they're not," Hill notes. "For me, it's usually a good sign if they're not."

David Packouz did make himself available, however, and even has a cameo in the film, as a guitar-playing singer in a retirement home. "A lot of times, it's better to hear about someone through people who were in their lives at the time you're playing them," Hill adds. "If someone was playing me, I'd give them the version I'd want them to put on screen, and if you were talking to my friends, you'd probably get a more accurate portrayal of me, warts and all."

The friends make some morally questionable decisions in the movie, but it's Diveroli who's seen as the driving force. "I think the whole time, David is trying to put blinders on what he's actually doing, whereas Efraim, not only is he not putting blinders on, he genuinely seems to be proud or excited by it, and I think that's just an interesting character trait.

"Anyone who knew him said the same thing - even though he was manipulative and deceitful, you did love being around him," adds Hill. "He was very charismatic and charming, so I found that a really cool challenge to play."

He admits he relished perfecting Diveroli's distinctive look, too: "The gold jewellery, the loud Miami clothing, the slicked back hair..." The tan was a different matter.

"The spray tan was tedious," Hill teases, grinning. "This lovely woman, Felicia, would come to my room every other night and hose me down. We got to form a really deep relationship."

In contrast to Dervoli's extreme nature, for Packouz, Phillips and his team "wanted an actor who could be a really effective counter-punch".

"We watch the movie through his eyes, so it was important that he be really sympathetic and grounded, and Miles Teller, who starred in 2014's acclaimed Whiplash is just a really gifted actor," says the director.

Cooper makes a brief appearance as well, as one of the biggest arms dealers of them all, Henry Girard, an amalgamation of shady characters from that world. The few scenes he's in were mostly shot in Vegas, the birthplace of The Hangover.

"It was a little bit like a homecoming," Phillips admits of returning to Sin City. "They take good care of us."

Befitting of the global scale of the story, film locations also included Jordan, Morocco, Romania, Miami and El Centro. "The biggest challenge is that it takes place all over the world, so we were never not travelling," explains Phillips. "That's always a bit of a logistical nightmare for the cast and crew, waking up with jet lag in a new city and just hitting the ground running.

"I thought it was really important because it brings a level of chaos to the set, and that chaos always finds its way into the movie."

Travelling is Phillips' favourite part of movie-making, and he confesses he thrives on disorder.

His next project, also co-produced with Cooper, is a TV series about the rise of ISIS. "We optioned this book that won the Pulitzer Prize for Nonfiction, called Black Flags, and it's something we're just getting going for HBO," he confirms.

Hill, meanwhile, is looking to produce a movie with Leonardo Di Caprio, about the security guard accused of terrorist activities during the 1996 Olympics. "It's a really amazing, heart-breaking story and we're trying to find a director for that now."

He's perfectly aware producing movies can be a tough slog - but it's worth it for the right project. "To make a movie and to make it good, you've got to give it all your heart," Hill adds. "If it wasn't something I was passionate about, then I don't think I'd want to do all of that work."

War Dogs is in cinemas now