If there's one benefit of playing a real-life character, it's that you have an abundance of information at your fingertips.

That was the case for Josh Hartnett, 42, when approaching the role of Victor Malarek in new film Target Number One.

The crime-thriller is a fictionalised account of an investigation that was made by Toronto reporter Malarek in 1989.

The story follows French-Canadian Daniel Leger (based on real-life figure Alain Olivier), played by Antoine Olivier Pilon.

A former drug addict, who was trying to get his life back on track, he was sentenced to 100 years in a Thai prison, where he endures torture and abuse, after being forced into a dangerous drug deal against his will.

When Malarek discovers it's a twisted case of entrapment, he vows to fight for Leger's freedom, and track down the shady undercover cops benefiting from the conspiracy.

"I was able to go meet Victor in Toronto," recalls Hartnett - who was born in San Francisco, but grew up in Minnesota - when discussing the preparation for the film.

"I was living in New York at the time, so I was able to fly up there and I spent the day with him.

"He showed me around his old newspaper, The Globe and Mail, he showed me his favourite sandwich shop and brought me to meet his family, and I grew to really understand what he was about."

The Pearl Harbor actor, who first came to audiences' attention in TV series Cracker, elaborates: "I saw a softer side to him than was portrayed in some of the media on him.

"And in his books, he has a lot of bravado and so it felt, to me, like the character became more and more whole and not so much a one-dimensional thing. I was really excited about playing him."

Target Number One is written and directed by Daniel Roby, who says the film came about after he attended a lawsuit in 2008 "involving RCMP [Royal Canadian Mounted Police] agents who were accused of coercing a heroin addict into a risky drug smuggling venture out of Thailand".

"In 1988, the deal orchestrated by the RCMP had led to a Bangkok trial and a death sentence ruling for the drug addict, who was wrongfully thought to be a drug dealer importing large amounts of heroin from Thailand into Canada.

"At the time, the Thai court verdict ruling went against the junkie, due to RCMP officers knowingly falsifying [allegedly] their testimonies in order to cover their unjustifiable investigation which ended up costing Canadian taxpayers over a million dollars (and a RCMP agent's life).

"Thankfully, the junkie had the support of a stubborn reporter, Victor Malarek, who sensed foul play by the RCMP and helped him battle the Canadian legal system."

He crafted the screenplay for Target Number One from testimonies he heard - including those from RCMP officers - as well as news articles, plus interviews conducted with Malarek.

"It was a long time ago and all these police officers are retired now, and none of them, I don't think, were reprimanded or anything," notes Hartnett, whose partner is actress Tamsin Egerton (they have two children together).

"I don't think there were any official problems made for them after this all came out. But I don't know ... Still today, there's a lot of people on edge about it."

Playing Malarek certainly sounds like it was fascinating to explore.

A Ukrainian rebel reporter, he could have been part of the Mafia if he hadn't discovered journalism in his 20s.

He was raised in tough reform houses as a teenager, and his hope, through being a journalist, was to uncover crooks that abuse innocent victims that were being forgotten by society.

As Target Number One unfolds, we see him struggle to balance life as a first-time father with his obsession with his job. But he is determined to expose criminals.

Everything about Malarek in the film seems autobiographical but, as Hartnett explains, they had to fictionalise other parts of the story in order to bring the story to life.

"We couldn't use the term RCMP because there are different laws in Canada than I think there are in the UK, and definitely in the US, about portraying officers of the law in film.

"So we had to sort of make a fictional version of them. And, also, because this case is a kind of a national scandal, we had to use a fictional name for him [Alain Olivier] as well.

"But everyone knows Victor, my character, wrote a book about it called Gut Instinct, and everyone knows this is about Alain Olivier.

"It's just the way we had to do it for the film."

As well as all the research Hartnett did into his character, he also went on an amazing moustache and hair journey ahead of being on set.

He chuckles at the suggestion the look is reminiscent of Trip Fontaine, his character in one of his most memorable roles: 1999 black comedy, The Virgin Suicides, which was written and directed by Sofia Coppola.

"Well that's what Victor looked like at the time; I didn't take any liberties!" he follows.

"If you see pictures of him at the time, I did the best I could to replicate that - and I've got more interesting facial hair right now.

"Unfortunately, this is as much as I grow in reality," he adds, on-camera over Zoom. "But I'm just starting another film now in Paris, so this is the way the director wants me to look."

It's the middle of July when this interview with Hartnett takes place; he was in Paris at the time, just as it was coming out of lockdown, and he quips "to be able to get out of the house is exciting".

He headed to the French capital to make Raoul Peck's new film, which he reveals was the first production to get going in the country after everything stopped because of the Covid-19 pandemic.

"He did I Am Not Your Negro a few years ago and he produced Lumumba, which is a fantastic movie," says Hartnett of the appeal of the project.

"And he is an old friend; we did a film together about 15 years ago. This is another sort of documentary-style film in which he takes his own experiences and threads those into the story, and it's about the history of genocide in western culture.

"He's also inserted these narrative pieces that I'm going to be a part of and I'm playing a very bad character."

Target Number One is now available on demand.