The plan was to meet Joe Alwyn at an old‑fashioned pub in the area of London where he grew up. It’s a nice pub, tiny, a selection of beers with wacky names on tap, percentage proofs that would make your eyes water. But we both arrive just before noon, and the doors are locked, so we awkwardly hang around outside, peering in through the window, looking to all the world as though we are desperate for a late-morning drink.

I am not sure that Alwyn is as desperate to speak to me, though over the course of a slow and steady pint, he is very polite and easy company. The actor, 31, has been on the brink of being a big star ever since he left drama school in 2015, but his route to fame has run at a slightly different angle from his route to acting success. His partner is Taylor Swift, one of the most famous women on the planet, so there is that. He is tall, handsome, with floppy 90s heart-throb hair. He is quick and funny and confident, low-key in a fleece and jeans.

For a while, we are the only people in the pub. He uses humour to deflect awkwardness, and I suspect it suits him that nobody can hear what we’re saying. Alwyn is about to star as Nick, the married, maudlin actor who has an affair with a student, Frances, in Conversations With Friends. The adaptation is the second of Sally Rooney’s novels to be made into a television series, after the lockdown-fuelled smash hit Normal People. The director of both, Lenny Abrahamson, said he cast Alwyn as Nick in part because he was “soulful”. “What does that mean?” Alwyn splutters. You tell me, Joe. “I’ll take it. I don’t know! So soulful,” he repeats, with a hint of embarrassment.

Rooney had a say in who played her characters. “I was told she was doing this and that,” he says, waggling a thumb up and down. “I mean, not literally doing that, like a gladiator or an emperor. She was involved in casting and watching tapes.” When he got the part, due to his soulfulness presumably, he contacted the author, and they exchanged a few emails. The shoot was going to be in Dublin, where they planned to meet, but late in the day it moved to Belfast. “So we didn’t. But I sent her an email just being like, ‘Thank you’, basically. Thanks for the thumbs up, Sally.” Rooney’s books are full of highly articulate emails and texts. “She does a good email,” he nods. So how did you approach the pressure of emailing her? “Many, many drafts. I did my best email. It just felt really nice to have her blessing.”

Alwyn had read Conversations With Friends and Normal People already, long before his involvement in the former. “I read Normal People before I knew they were making a show out of it, and I remember when I saw it thinking, I’d love to be in something like that.” Normal People’s sex scenes between Connell (Paul Mescal) and Marianne (Daisy Edgar-Jones) became such a talking point that people began to lust over Mescal’s silver chain, as if everything else about him had been exhausted. In Conversations With Friends, Nick has a heated affair with Frances, and Alwyn is fairly regularly, if tastefully, naked in it. “We were guided through it with an intimacy coordinator, Ita O’Brien, who is great,” he says. “They’re essentially choreographed. So they’re like fight scenes. They’re quite mechanical. And obviously they’re weird, funny, strange things to do with your friends. But when Lenny’s in the room, cracking jokes, and there’s 10 crew members around, and it’s freezing cold or boiling hot, it just takes all the sexiness out of it.”

Besides, he says, the sex scenes are there for a reason. “They are kind of extensions of the conversations, in their own way. Each one, hopefully, should feel slightly different and mean something different to the people involved, and they’re not just kind of gratuitously thrown in. But, I mean, obviously, it’s a weird part of the job.”

Normal People and Conversations With Friends are different stories, and different series, in many ways, but if his series follows the Mescal trajectory, is he prepared for the idea that he might become a pin-up? “I honestly just don’t have any thoughts about it,” he says. They only finished filming four months ago. “I haven’t let myself think, ‘Oh God, people are actually going to see it’, so I haven’t thought about that side of things. Which is a boring answer, I know.”

Anyway, this is a serious drama, not a bonkbuster, and it deals with serious themes. Nick is married to Melissa (Jemima Kirke), a successful writer, and their marriage has not always been monogamous. But when Frances (newcomer Alison Oliver) and her best friend and ex-girlfriend Bobby (Sasha Lane) start to entangle themselves in their lives, the four of them are forced to ask grownup questions about love, jealousy and honesty. Nick is certainly a complicated character who runs hot and cold, and he is difficult to pin down. “When you meet him, he’s in a place of recovery – he’s been through a storm and is slightly numb to the world. And he’s just kind of functioning, and we meet that version of him, but we don’t really know why,” Alwyn says. It isn’t until later in the series that we start to learn who he is. “He can be a real enigma, and sometimes frustratingly so. He’s quite aloof and enigmatic and unreadable.”

I am not sure that Alwyn is aloof, but he has more than a touch of the enigmatic and unreadable about him. He has been a steadily successful actor since 2016, when his first job was to star in the Ang Lee-directed Billy Lynn’s Long Halftime Walk, alongside Kristen Stewart. He followed it up with smaller roles in a series of award-winning films, including The Favourite, Mary Queen of Scots, and Harriet. He has fronted campaigns for Prada, and has also won a Grammy, after collaborating with Swift on her 2020 album Folklore. Despite all of this, I say, I don’t know very much about you. Few details of his life are public, which he seems to prefer, but it does mean we have to start at the beginning. So you grew up …

“I grew up in this pub,” he cuts in, grinning. “I was born in this garden and I’ve never left. Very happy here, thank you.”

He actually grew up near where we are today, in Tufnell Park, a well-to-do neighbourhood in north London. His mother is a psychotherapist. “I never felt like I was lying down on the couch and being analysed every evening, which is probably a good thing. I managed to escape that. But she’s great with people and great to talk to. People always think that must be strange, having a mum who’s a therapist.” Well, it is interesting. “It definitely is. It’s an amazing job. I actually think if I didn’t do this, I would be interested in doing something like that.”

His father is a documentary film-maker who also teaches film-making. He instilled a love of films in the young Alwyn by giving him stacks of VHS tapes for his birthday and Christmas presents. “He makes fly-on-the-wall, observational human stories. When I was growing up, he was often away, and I remember him being in these far-flung places a lot, bringing back cool gifts for me and my brother.” Did you ever go with him? “I was never invited.” He leaves a beat. “Don’t worry, I spoke to my mum about it,” he quips.

He has two brothers, one older, who works for an NGO, and one much younger, who was born when he was at secondary school, and has just left school himself. Alwyn went to a private boys’ school, on a scholarship and bursary. He enjoyed it, and made a group of friends that he still speaks to all the time, even today. He didn’t really act at school; he mostly played sport. “I was good at football. Tennis. I just like athletics, generally.” He squirms. “‘Just generally’. It sounds so arrogant! ‘All of them’.”

Were people surprised that he wanted to be an actor? “I feel like I’d given enough hints that it wasn’t a complete bombshell when I wanted to do it, but I do think there was probably a feeling of, why?” He studied English and drama at Bristol University, and then went to drama school in London. Immediately after his final showcase, so the fairytale version of the story goes, he signed with an agent and was asked to audition for Lee, the Oscar-winning director of Brokeback Mountain, Sense and Sensibility, and The Ice Storm.

Was it really that simple? “It was as mad as that,” Alwyn says. He sent over a tape, and got a call saying Lee wanted to meet him that weekend. “So they put me on a plane. I hadn’t been to America before.” He landed in New York, in the snow, and immediately went out to find a New York slice of pizza. “Within five days, I’d left school, had a visa and was in boot camp in Atlanta. As it went on, I managed to relax and enjoy it. But at the beginning, in the first week or two of shooting, I was shitting myself.” And then it was over. “Everyone else stayed in America. I had to go back home and walk the dog the next day, it was pouring rain and I was back in this garden,” he smiles. “And life continued.”

After Billy Lynn, Alwyn had a run of nasty characters, historical figures, and sometimes both. He was a slave-owner in Harriet, and the son of a Nazi in Operation Finale. In The Favourite, he has a comic turn as Masham, who seduces Emma Stone’s Abigail, dances a silly dance with Rachel Weisz as Lady Sarah, and is a thorn in the side of Olivia Colman’s Queen Anne. “All three of them are amazing. Just down-to-earth, funny, nice people.” He says that it is fascinating to watch Colman work. “Because it can be so easy to sit in the corner full of nerves hyping yourself up for a scene, but she is so chilled and fun and cracking jokes, and then she’s just in it and out, and then it’s done.”

Masham is a supporting character, a small-ish role, but Alwyn decided early on that he would rather take smaller parts with directors he admired than always go for the big, splashy jobs. “There are a couple of things I probably did just because I wanted to work, but I’ve tried to be pretty picky,” he says. Does that require a healthy ego, to be happy to play the supporting role, rather than insisting on being the star? “The idea of being the lead role just for the sake of it seems ridiculous,” he says, then catches himself. He likes to make sure he is being understood. “Well, it doesn’t seem ridiculous. Each to their own. But I’d much rather play an interesting support role in an interesting film. I find that more attractive.”

***

Since 2016, if the internet is to be believed – details are sparse, and will remain so, largely – Alwyn has been in a relationship with Swift. His film career brought him a level of recognition, but the level of fame he has been exposed to around his relationship is something else entirely. Was that a shock? “It’s not something I think about, unless I’m in situations like this, and someone says, ‘What’s it like?’ and I have to think about what to say about it,” he says, though he does have plenty to say on it, which suggests he has thought about it at least a little bit. He is more clipped when he talks about this side of things, and a bit less jokey, as if practised in being firm. “It’s just not for other people,” he says, of their relationship. “And I don’t say that with aggression.”

He will concede that he can see why people might be interested in it. And people are interested. Her 2019 song London Boy, about fancying a charming, sporty north London boy with lots of mates, is rumoured to be about him, but, other than that, they say very little about each other in public. I tell him I watched a nine-minute compilation on YouTube that collected everything they had said about their relationship in public into one handy video. “Well, I hope that was illuminating,” he says, drily. It wasn’t, actually. “That doesn’t surprise me, because I don’t know what people would be going off.”

He pauses, for what seems like an age. “I don’t know how best to talk about it. I mean, I’m aware of people’s … of that size of interest, and that world existing. It’s just not something I particularly care about, or have much interest in feeding, I guess, because the more it’s fed, the more you are opening a gate for intrusion.” He is aware that this makes him sound guarded. “I think that’s just my response to a culture that has this increasing expectation that everything is going to be given. If you don’t post about the way you make your coffee in the morning, or if you don’t let someone take a picture when you walk out of your front door, is that being private? I don’t know if it is. So I just don’t really feed that.”

His own Instagram is strictly work-based, and there is little hint of anything beyond a film set. “If you and I were having a conversation, and having a shandy in my house, and it wasn’t being recorded, then, of course, other things would be said,” he says, echoing what Swift told this paper in 2019. (“If you and I were having a glass of wine right now, we’d be talking about it – but it’s just that it goes out into the world,” she said, back then.) Did they decide, from the beginning, to have a party line, and not to talk about each other? “Erm. It was just like, well, why? There are more interesting things to talk about and I just think it feeds into a weird part of the culture that I’m not really interested in being a part of.”

One thing he will talk about is their musical collaboration, which turned him into a Grammy winner. I did want to ask about music, I say. “Go for it, and I will sing for you,” he jokes, happier to be back on solid ground. When Swift released Folklore, two of the songs, Betty and Exile, credited a mysterious co-writer called William Bowery. Fans speculated as to who it might be, and Swift later revealed that it was a pseudonym for Alwyn, who also co-wrote some of the songs on its follow-up, Evermore. “That was a surreal bonus of lockdown,” he says, checking himself. “That’s an understatement.”

What was it like to work with your other half, in her line of business? “It wasn’t like, ‘It’s five o’clock, it’s time to try and write a song together,’” he says. “It came about from messing around on a piano, and singing badly, then being overheard, and being, like, ‘Let’s see what happens if we get to the end of it together.’ ” He liked it because there were no expectations and no pressure. “I mean fun is such a stupid word, but it was a lot of fun. And it was never a work thing, or a ‘Let’s try and do this because we’re going to put this out’ thing. It was just like baking sourdough in lockdown.” But not everyone’s sourdough resulted in a Grammy. “The Grammy was obviously this ridiculous bonus.”

Did he have any musical ambitions before this? “I like music, and I played a bit of guitar awfully in a school band when I was 12.” They were called Anger Management, and they covered Marilyn Manson’s version of the Eurythmics’ Sweet Dreams (Are Made of This). “I can play piano pretty badly, but never with the intent of, ‘Right, it’s time for my jazz-fusion album.’” He grins. “Unfortunately.”

He’s joking, but if a jazz-fusion album does emerge one day, it wouldn’t be such a curveball. He is about to take some time off and has no immediate jobs lined up, he says, which is fine by him, as last year was so busy. His recent work indicates a Robert Pattinson-style swerve into the arthouse. He had a small role in Joanna Hogg’s The Souvenir: Part II, and his next two films will be Stars at Noon, an adaptation of a Denis Johnson novel directed by Claire Denis, and Catherine, Called Birdy, a medieval comedy directed by Lena Dunham. “Again, I think that all comes from working with Ang Lee, and the luxury of that at the beginning,” he says. “I would just much rather do that for now and ‘build’, which sounds awful,” he says, beginning to collapse into a cringe, “and like, oh, grow as an actor, which also sounds awful.” He looks mortified. “Do you know what I mean?”

I think I know what he means. He sounds like someone who is satisfied with life as it is, and where it’s about to take him. We finish our pints. Alwyn is heading off to meet someone on Hampstead Heath, and we shake hands, politely, as we say goodbye. He heads out into the street, eyes on the path just ahead.

• Conversations With Friends starts on BBC Three and BBC iPlayer on 15 May.