This feature originally appeared in the May issue of InStyle. For more features like this, subscribe to the magazine now. And be sure to catch James McAvoy in Filth, in theaters May 30th.

In Filth James McAvoy plays an abusive, erratic psychopath. It’s a character he inhabits so convincingly that when you meet him for coffee and a chat, you will startle, embarrassingly so, when he reaches over to pour you some milk.

For the film adaptation of the Irvine Welsh (author of Trainspotting) novel of the same name, McAvoy, 35, portrays a crooked cop on the brink of a nervous breakdown. The emotional strain is reflected in a savage mean streak and moments of vulnerability. The role is an outlier in his body of work—which includes The Last King of Scotland and X-Men: Days of Future Past, the latest film in the series—in which his characters shine with charm and likability.

Today at a bustling lunch spot in Manhattan’s Chelsea neighborhood, McAvoy, wearing a denim work shirt and carrying a nylon backpack, conveys a look that is half cool dad, half dorky grad student (he even has a very normcore digital watch on). The movie-star blue eyes, however, command your attention the way a forehead tattoo might. They light up to punctuate profanities (every other word) and stay lit when he makes fun of you for being so skittish.

I had no idea your facial hair was quite this ginger.
Yeah, my beard is plenty ginger; sidies too. I’m a full-on f—ing carrot face.

You’ve been cast quite a lot as the boyish charmer, but you are squarely middle-aged as Bruce Robertson in Filth.
All through my 20s people would send me scripts where I’m 18, yet now I know that can’t happen. Which is a good thing, but in no way did I think I could play a 40-year-old. I loved the character and script so much and thought if I saw anyone else play him, I would be devastated.

You’re in a scene with your real-life sister, Joy, and it’s brutal. How was working together?
Weird, because I have to abuse her—but she’s an amazing actress, so sharing the experience was really cool. Not everybody gets to work with their family, and she’s one of my favorite people in the world.

Your wife, Anne-Marie Duff, is also an actress; you met on the set of a TV show. Would you want to work with her again?
Yes and no. We’ve got a kid (a son, Brendan), so if we’re working on the same thing, then somebody else is looking after him. And that’s not good.

Acting is but one of your talents. There’s also your teenage-band years. You played bass?
There were a few bands. One was called Shoo-glenifty, a name we took from a real band, which means “dance with skill.”

Do you dance with skill?
I would say I’m a committed dancer. I dance to funk mostly, some cheesy disco—the cheesier, the better.

In the next X-Men you and Michael Fassbender play mutants in the ’70s. How do you feel about that era, style-wise?
Fassbender hates it, but I love the clothes. I actually owned a pair of brown bell-bottoms—not for a role—that were maybe slightly too tight for me when I had them.

I’m glad to see your red-carpet looks are more classic.
I’d run a mile from a suit if I could, but if I have to wear one, it’s Prada or Burberry.

This next question is important: Did Atonement co-star Keira Knightley really claim you were a better kisser than Johnny Depp?
And Orlando Bloom! It was in the headlines in Scotland. It was great!

For more, turn to page 146 of InStyle’s May issue, now available on newsstands and for digital download, and check out the 20 hunkiest Men of Style featured in InStyle in our gallery!

—Mary H.K. Choi