It’s been three years since I’ve spoken to Colin Farrell, and for some reason I’m shocked to see that he – like my own mere mortal self – has aged. The last time we spoke, we were curled up in armchairs in a Dublin hotel over tea. His hair was long, his manner effusive. Now, in a swanky LA suite with the AC blaring, our Colin’s hair is short and graying, and his demeanour is more subdued. He’s no less friendly or engaging; Farrell’s innate magnetism could never be extinguished. But his charm is less performative these days. Indeed, he now seems possessed of an assured stillness that exudes experience and wisdom.

This newfound calm is certainly at odds with the actor’s tabloid reputation of yore. For years, Colin Farrell was the Bad Boy, the Party Boy, the Playboy. But at 40, he’s no longer a boy, nor trying to be – he’s definitively, happily, all grown up.

Not that being older has eliminated his desire for magic and joy. Farrell is currently starring in Fantastic Beasts And Where To Find Them, a prequel to the Harry Potter stories. Directed by David Yates and written by JK Rowling, the film takes place in New York in 1926. The city is becoming increasingly dangerous, with battles between wizards and non-magical people (known as ‘No-Majs’) brewing. Oscar winner Eddie Redmayne plays Newt Scamander, a curmudgeonly wizard whose magical creatures are set loose across the city, escalating the tension and the fun. Farrell plays Percival Graves, a man struggling to keep things under control after Newt’s actions highlight the stark divides in society.

“Percival Graves is the Head of Magical Security at a place called MACUSA, or the Magical Congress,” explains Farrell. “So I uphold the law, basically, in the society of wizards in the North of America. But MACUSA is also a centre of international dealings in the wizarding world, because in North America there’s a greater divide – greater than there is in the Potter world back in Britain – between those who are born with magical attributes and those who are mere mortals. So there’s a veil of secrecy around my work, and if there is any dark arts or black magic performed, I investigate that.”

Percival Graves is Farrell’s first feature role since he starred in Yorgos Lanthimos’ affecting satirical drama, The Lobster. Addressing loneliness and control, Farrell’s character was awkward and obviously overwhelmed with sadness and a lack of self-worth. Farrell loved working on the project, but it seemed both emotionally an physically gruelling, as he put on over 40 pounds in eight weeks to play the role. In contrast, acting in Fantastic Beasts was a dream.

“It’s kind of hard to method act or do research on wizards,” he laughs. “You can only twirl your wand in your hotel for a few minutes before you start to feel ridiculous!”

Farrell hasn’t starred in an unapologetic blockbuster like this in years, but the finely drawn characters and intricate world of JK Rowling’s script drew him in.

“It was all on the page,” he enthuses. “JK Rowling wrote such a beautiful, incredibly descriptive screenplay, it was so perfectly formed. The characters are all so finely drawn and the world itself is New York, albeit a New York of a bygone era. It’s a New York that is not familiar to me experientially, but is familiar from film. Yet she tilts the perspective a little bit by imbuing it with this sense of magic.”

Farrell, who has worked with a lot of CGI over the years – don’t mention the flying horse from the dodgy 2014 fantasy A New York Winter’s Tale – was delighted to see that director David Yates brought as much magic to the filming process as possible.

“One of the great things about shooting this film,” says the actor, “was that even though the sets were huge, they were also practical. Our work was physical and grounded. There were things that were added in after – the magic, how big the city needed to be – but everything we needed was there. They built the most incredible sets, they were just astounding. I’m 40 and have been doing this for 20 years, and even I was like, ‘Wow.’”

As well as marking the first clear blockbuster and possible – probable – franchise film Farrell has done since the 2012 critical flop Total Recall, it also sees him tackle yet another role we haven’t seen him play before: the rule-keeper. Previously Farrell has played the straight man in Seven Psychopaths, Alexander and The Recruit; wayward characters in Intermission, In Bruges and Dead Man Down; emotionally fragile figures in Ondine, Saving Mr. Banks and Crazy Heart; and unabashed lunatics in Horrible Bosses and Fright Night. But never before have we see him play an authority figure.

“I try to play different characters,” agrees Farrell. “It’s not just for the sake of doing something different. When I’m choosing roles, it’s more fun when you change it up. It’s more challenging, and it staves off any apathy that may creep in. I mean, this is an amazing job, but you can get apathetic about anything. So for me it’s nice to play characters who are from different periods and different socio-economic backgrounds.”

It’s both this attraction to the new and challenging, as well as Farrell’s raw talent, that prevented him from becoming the straightforward leading man that Hollywood expected him to be. Eschewing offers to be a romantic lead or action hero, Farrell focused on balancing large Hollywood productions with independent films. He says that he was rarely attracted to generic leading men roles, and was more drawn more to characters who are emotionally conflicted.

“Some characters are closer than others,” he muses. “You may feel an echo of something that you’ve done before, which is natural enough, but you can’t get away from yourself.”

It’s thus unsurprising that Farrell’s latest films have reflected on his most important role in life: being a father. His sons James and Henry are now 13 and 7, respectively. Raising them has made Farrell acutely relate to films that address fatherhood, family, and loneliness – as well as making him more eager to embrace the innocence and whimsy that his children embody.

“I think it’s very easy to get bogged down in the negativity and discord in the world,” he remarks. “Yes, there are terrible things happening, but there are also beautiful things – they’re just not reported on as much. You don’t want to be foolishly optimistic or in denial, but you need to maintain a balance.”

However, Farrell denies being over-protective of his sons, assuring me that he’ll never turn into a helicopter parent.

“I just let my boys be boys,” he says. “Often times with kids, if you just stay out of their way, they’ll be fine. Of course you need to guide them, but trusting them is important too. Perhaps an even bigger fear than something happening them, is them not knowing that I love them. One of my guys actually told me, ‘Stop saying you love me!’ If that’s the worst we go through, that’s not so bad.”

He’s also learned the hard way not to make films just for them.

“You hope that they’ll be able to enjoy it,” says Farrell. “But you can’t count on it either, because they might not, and that’s fine. I did do an animated film and they weren’t big fans of it, which was depressing – it really was! They were just like, ‘Yeah, whatever, can you put on Wreck-It Ralph again?’ When I was working on Fantastic Beasts, one of my little men got a wand and was happy with it for about two minutes, before he moved on!”

But even with the wands and wizardry, Fantastic Beasts has some hard-hitting themes. The film addresses the danger of segregation and social hierarchies, with wizards divided over the roles and rights that No-Majs should be afforded. Even through the thick layer of fantasy and magic, the theme feels uncomfortably prescient, particularly with the US Presidential election happening hours after this issue goes to print.

But even within the privileged environment of Hollywood, matters of segregation and inequality have dominated the cultural conversation. The gender pay gap and lack of racial equality are among the issues to have been highlighted. In recent times, the dialogue has shifted again. The question is now: are the players in power – ie. white men – voicing their desire to see oppressed groups equally represented?

Orange Is The New Black actor Matt McGorry constantly speaks out about the need for feminism and racial equality on and offscreen, while Bradley Cooper has criticised Hollywood after finding out that actresses like Jennifer Lawrence and Sienna Miller were offered less than their male co-stars. Harry Potter alumni Daniel Radcliffe and Emma Watson, meanwhile, have also voiced their concerns about the lack of racial diversity and gender equality in the industry.

Meanwhile, JK Rowling, queen of all our hearts, beautifully shut down demands that actors in theatre adaptations of her work be white. When Noma Dumezweni was cast as Hermione Granger in Harry Potter And The Cursed Child, the author responded to racist demands for a white actress by tweeting “Canon: brown eyes, frizzy hair and very clever. White skin was never specified. Rowling loves black Hermione.” When trolls persisted, asking “How come you cannot find even a good white actress?”, Rowling answered, “We found the best actress and she’s black. Bye bye, now.”

The Almighty Creator had spoken.

However, Farrell seems decidedly uninformed about the current discourse surrounding Hollywood and diversity, claiming apologetically, “I don’t know how the controversy is being handled. I’m not being coy, I promise, I just literally don’t know what’s happening.”

Farrell’s ignorance is less to do with a lack of awareness of, or passion for, equality, and more to do with his lack of engagement with Hollywood as a culture. A far cry from his younger days of partying and tabloid coverage, he now rarely attends Hollywood soirees or award ceremonies, preferring to focus on work and family. But even without knowing the specific details of #OscarsSoWhite or the wage gap controversy, Farrell is unequivocal in his beliefs.

“The race line shouldn’t be defined in something like film or the arts,” he says. “And there’s absolutely no way that a man should receive more than a woman for a part of equal size. There’s no way.”

Asked whether he has ever seen misogyny or racism play out behind the scenes of film productions, he says “never” – but he’s also aware of what he doesn’t know.

“I’m not privy to the behind the scenes stuff,” he says. “I’d prefer to stay out of it all. It’s not that I don’t like getting my hands dirty with certain topics or conversations – if I see something like that, I’d say something immediately. If I was ever aware of any misogynistic behaviour on a set, I truly wouldn’t have stood for it. I just haven’t seen it. But then how far back do you want to go, obviously there’s the casting couch...

“Do you know though, there is one thing that I was thinking about recently: I’ve only worked with one female director. And I don’t know who to blame for that. But there’s no doubt that it would be harder for a female director to get financing for a film, just by the virtue of the fact that most financiers would be male and would be suspicious. They would have some ingrained, sexist belief that a woman would not be as strong or as capable as a man. That is something that’s societal and needs to be weeded out over generations, starting yesterday.”

Promoting empathy and equality is something particularly close to the actor, as his eleven year old son James was born with Angelman Syndrome, a developmental disorder. Raising James inspired Farrell to become an advocate for many charities and awareness groupss. He is a supporter of the Foundation of Angelman Syndrome Therapeutics, and was on the panel of the Special Olympics in China. His experience raising a son with a disability and working with others with similar challenges have cemented for him the need to teach acceptance.

“It all has to start at home and in the schools,” he asserts. “Because any storyteller or artist was brought up in a family or orphanage or group environment, and had some form of education, informal or formal, from the adults around them. This is grassroots stuff, stuff I’m talking to my kids about everyday.”

Farrell, who has lived in Los Angeles for over a decade, admits that he is largely disengaged from Irish politics, saying that, “My Irish friends are still the same friends I’ve had since I was 13, but as for political stuff, I’m just busy trying to be a Dad.”

He did tune in for Brexit, however, and was dismayed at the result. The similarities between the racist, anti-immigrant sentiment being expressed in the UK and those being expressed by some Americans during the Presidential elections were not lost on him.

“Look, the world is a grossly unfair and biased place,” he laments, shaking his head. “It’s filled with bigotry and inequality, but we’re clawing our way towards what feels like a more just society. And yes, minority races and ethnicities have had a much harder time than the majority, and that’s the cruel nature of power as represented by human beings. And women have been on the outside of so many experiences that they should never have been on the outside of. But I think it’s getting better.”

He pauses again, conflicted between his boyish faith that the world is good, and the careworn wisdom of a man who knows that life is rarely that simple. “I think. I hope.”

Fantastic Beasts And Where To Find Them is in cinemas today!