Alexander Skarsgård and Harry Melling on the surprisingly sweet BDSM romance ‘Pillion'

Alexander Skarsgård doesn't usually watch his movies more than once with an audience. But ''Pillion,'' in which he plays the enigmatic member of gay biker club who begins a dom-sub relationship with a younger, more inexperienced man, Colin (Harry Melling), has been an exception. He's seen it at least four times.

It's partly because ''Pillion'' has been coming out for so long. The film premiered last year at the Cannes Film Festival before going on to play at several others and is just now arriving in North American theaters. But mostly it's because it's a film that is never not interesting to experience with a crowd: It's both remarkably explicit in its depiction of sex and surprisingly sweet and comedic as Ray (Skarsgård's character) and Colin navigate the dynamics of their unconventional relationship.

''It can play in so many different ways,'' Skarsgård said in a recent interview. ''It's really fun to see and feel the energy in the room, how sometimes people really lean into the comedy and sometimes it feels more somber and heartfelt.''

Skarsgård was joined by Melling and filmmaker Harry Lighton for a lighthearted conversation about sex on screen, ''Heated Rivlary'' and why Melling, who since his days as Dudley Dursley in ''Harry Potter'' has become a bona fide character actor, would prefer to keep the word ''breakthrough'' out of this moment.

Remarks have been edited for clarity and brevity.

AP: There's been some comparisons to ''Babygirl,'' which stirred debate over whether it's sex positive or negative. Do you see ''Pillion'' in one of those lights?

LIGHTON: It's hard for me to reduce it to sex positive or sex negative, because I think that there are ups and downs to Colin's experience. Maybe I'd call it ''sex net positive,'' which is an incredibly unsexy way to describe the film. That's not going to get bums on seats at all. But for me the film's about someone trying to grow into his sexuality. And that's always going to be a bumpy road. But where he ends up is with more knowledge and practice.

LIGHTON: I had to fight for the odd piece of technical equipment or an extra day in the schedule, all that boring stuff. But not the stuff which I thought was really integral to the script, for instance, not sanitizing the depiction of sex. I was very keen on the fact that if we were going to take on this subject matter that the sex would be on screen, that it wouldn't be like portrayed through ellipsis or the camera panning away because I thought would make it seem like I was judging the type of sex we were showing. But I was very well supported in that aim by all of our execs.

SKARSGÅRD: The screenplay was way more explicit than the final movie. You made sure that anyone who read the screenplay knew what they were throwing themselves into.

MELLING: You really did know what you were saying yes to.

LIGHTON: Actually, in a way, you didn't because you thought you were saying yes to a five-minute shot of an erection.

SKARSGÅRD: I'm like, what kind of Disney version of this movie is that?

SKARSGÅRD: I love the little clues that Harry put into the screenplay and the fact that it's never really spelled out. There's never a big cataclysmic moment where he's opening up about his past or about a secret life.

It was a lot of fun finding little things that would add a flavor to the character of this dominant biker, everything from what book is he reading, what glasses is he wearing, to what are the tattoos on his body? Maybe they're more effeminate. Maybe he's listening to like, ''I Think We're Alone Now,'' you know, like pop music from the '80s.

And I'm really pleased that he remains enigmatic.

AP: Would you say this is a breakthrough role for Harry Melling?

LIGHTON: He's done lots of roles which have merited attention and they're all incredibly varied, which is what I found so fascinating about Harry as an actor. But I also did it in a slightly greedy way. I thought it was really exciting that I would be able give Harry the opportunity to, I mean, this is your first lead feature film role. Is that fair Harry?

LIGHTON: The success of the film lives or dies by Colin so I think the reaction to the film is a kind of testament to Harry's work in it.

MELLING: I'll also add, this is like a side point, nothing about that, but like the idea of, you know, the word breakthrough terrifies me. If you as an actor start considering this is, like, the moment or the breakthrough moment, you're sort of done for.

SKARSGÅRD: And can we steer the conversation back to me now?

LIGHTON: I knew I knew that was coming. As soon as I said ''lives or dies by Harry's performance,'' I saw your face drop.

SKARSGÅRD: You saw the vacant, distant gaze of an actor when the conversation isn't about him.

SKARSGÅRD: I was texting my publicist, ''Get me out of this.''

AP: Do you think ''Pillion'' could be a ''Heated Rivalry'' kind of hit?

SKARSGÅRD: No. But I'm excited that it's coming out, finally. And the fact that people in the BDSM community seem to respond to it, but (Harry Lighton's) mom also loves it. Hopefully it can appeal to a lot of people.

MELLING: My parents also absolutely loved it. Sadly, I didn't see it with them, which I would have loved to. I know to a lot of people that would be shocking.

SKARSGÅRD: I watched it with my dad (Stellan Skarsgård), and he loved it. But maybe that's less surprising than like Lighton's mom with her friends going to watch it.