At the Cannes Film Festival, Jude Law looked like his usual self: the handsome British actor with a mustache, some stubble and the sparkling blue eyes that always seem to contain a twinkle of mischief. But watch him in Firebrand and you’ll find none of that, instead replaced by a looming, large, and often disgusting Henry VIII that is ailing at the end of his life and growing increasingly paranoid.

The film, which premiered on Sunday night, centers on King Henry VIII’s sixth and final wife, Catherine Parr, played by Oscar winner Alicia Vikander.  When Henry returns home from fighting overseas, he discovers that Parr has been pushing her radical views on the court. With his legs infected and in constant pain, Henry grows suspicious of his wife and begins to take action against her.

Law transformed in many ways to play the role, changing his hairline, adding a beard, and putting weights into his clothing, and, as he mentioned at the Cannes press conference, creating a perfume that smelled of “puss, blood, fecal matter, and sweat” that he would wear on set. “I read these several interesting accounts that at this period, you could smell Henry from three rooms away because his leg was rotting so badly. And he hid it with rose oil. So I just thought it would have a great impact if I smelled awful,” he says. 

Before the red-carpet premiere on Sunday, Law sat down with Vanity Fair to reveal more secrets to his transformation—though he’s still keeping some “movie magic” secrets to himself. 

*__Vanity Fair: __*What appealed to you about playing King Henry VIII?

Jude Law: The little I knew at that time of Henry meant that I was sort of excited at the idea. I thought, gosh, there's potential in that, surely. But meeting [director] Karim [Aïnouz] really redirected the potential journey because he saw it as a sort of domestic piece. He talked always about them as humans and as this abusive marriage, as husband and wife, rather than on this sort of pedestal of history of monarch. And so what that immediately meant I could do was just to start looking at him really from the layers right down to his childhood — what made him who he was? How do I make plausible and three dimensional and complicated? And that had a big effect then on the physicality. 

What were you surprised to learn about Henry VIII? Because I think we all know the tale of six wives, and about him in a more legendary way.

I think that's the surprise that we see it as this tale. There's this little ditty that's almost like a children's nursery rhyme. And instead you realize, no, he was a tyrant. He was a gangster, really. And he was paranoid and deluded and terrifying. And that's before you get into the fact that towards the end of his life, he was also suffering from incredible pain and was probably an alcoholic and abusing himself with what he ate and paranoid about his health. And so the research started with an awful lot of reading. And what I realized was there were a huge amount of known facts that all these books shared and an awful lot of interpretation that each of the historians have applied. It felt therefore, that we were able to make our own interpretations. 

It also meant that it felt I could really just concentrate on building him from an emotional perspective and then try and find a sort of authentic way to physically realize him. I didn't have enough time to gain 20 stone, and just having a little pop belly wouldn't have sufficed. So it was sort of important to physicalize him in a different way. I just sort of wanted to instead wear him in a different way. So we used weights and we used the costume. Obviously, the beard helped. I changed my hairline. There were all sort of little tweaks and little bits of movie magic.

What does “movie magic” mean these days?

I quite like the unknown. I quite like that there are little elements that I don't want to explain how we did it.

You must have thought a lot about his history that got him to that point in his life.

I kept thinking about the fact that I'm sure he still saw himself at times or felt at times like the 18-year-old god that he was when he was apparently the tallest man  — he was like six foot, blonde haired. He was a great dancer, a great musician, a great horseman, a wrestler. He was unbeatable. And he probably didn't go out meaning to have six wives. He met Catherine of Aragon and they were married for many years. And he probably thought, “I've got it sorted.” He just became obsessed with this legacy, this heritage of having a son. And it almost drove him mad.

In the film, even when he’s not going anything abusive at the moment, he always seems vaguely threatening. How did you accomplish that?

He had the privy council, a gang that were around him, and he created that because he wanted to remove himself from the privy chamber, which was a lot more advisors. He saw them as threats because they were all landed gentry. So he created this gang, and because they were all traders’ sons, they didn't own land, which meant they couldn't take his crown. And they literally wiped his ass. They looked after him, they washed him, they fed him, they cleaned him. They did everything. So we cast a group of actors I'd worked with before on stage. So I knew them all very, very, very well. And we had this immediate gang, so we went everywhere together on set. 

When it came to the look, how  important was it to actually resemble what King Henry looked like?

Obviously, there was always the guide of the portraits that we had to somehow resemble. So doing him without a beard would've made no sense. He had a huge beard. But I just didn't want to wear prosthetics. I didn't want to sort of make a mask of Henry and put it on my face. I wanted to find him more in me. And the makeup artist, Jenny Shircore, is really legendary and brilliant. So we changed hairline a lot. The beard helped a lot. We did certain — now I'm giving you all the secrets, you see — things in my mouth that changed the shape of my jaw. And the eyebrows, eye color, all of those, all little tweaks, tiny little tweaks. But they really make a difference together. I mean, you could probably take a look at the portrait of Henry and go, “oh, you don't look anything like him,” but you get a sense of him. It was important to make him real as opposed to cartoony. And I wanted him to sort of come out of me.

Does taking on a role like this where there is such a notable physical transformation ever feel scary or just exciting?

No, not scary. I love the challenge of it. That's one of the reasons I love making films and different characters, because, I mean, obviously this one's quite extreme, but I always feel like there's places to go, whether it's facial hair or changing my hair, or putting on a little weight or losing a little weight or whatever it might be. It's like getting the right smell for them. It's like getting the right shoes for them. The walk. They're all lovely details that take you away from yourself. And when you get it right, it's a sweet spot. It's a great moment from my perspective as an artist.