Sigourney Weaver has four films coming out between now and 2022 – three Avatars and an Alien sequel – most of which have yet to be filmed, and which the 67-year-old has prepared for by cramming in as many small films as she can in advance. This is a psychological as well as an acting necessity, a way for Weaver to fine-tune before the onslaught – and which, in the case of A Monster Calls, has resulted in an almost unbearably poignant movie. The film, adapted from the Patrick Ness novel about a child who loses his mother, is so finely wrought that when Weaver first read the script, she thought, “I don’t think I can be part of this, it’s too painful. And then you realise this is your job, to tell the story.”

In the original Alien in 1979. Photograph: Allstar/20th Century Fox

Weaver is bright today, in a studio just outside New York, with that friendly but slightly patrician air she puts to good use in the roles she does best: the ostensible villain who isn’t all that she seems. For someone as open as Weaver, she plays repressed very well, most notably Janey in Ang Lee’s The Ice Storm, but going back as far as Katharine in Working Girl, and even to Ripley in Alien, the film that established her as an actor able to convey large internal movement via the smallest surface ripple. These roles are often characterised as “cold”, which feels to Weaver like a gendered term designed to debase their humanity. “The male perspective may be that it’s a cold person. But in fact, like in Ice Storm, Janey was disconnected: she couldn’t focus on the present and her family. Bored and lost. But I would never have gone to ‘cold’.”

If she is optimistic about human nature, it is not only a requirement of her job – to inhabit another psychology requires deep levels of empathy – but of what appears to be her generous disposition. A small example: I am 30 minutes late after a train debacle, something that, with an actor of Weaver’s standing, would customarily cause upset on a par with the sky falling in, but is instead met with concern. Standing up from the lunch table to her full 6ft, and in a tweed jacket that speaks to an idea she has of England, she projects an amused frankness that she later describes, with some embarrassment that it should need to be clarified, as “normal”. One can be the sort of actor who shouts and screams and throws tantrums, but “honestly,” Weaver says, “life is too short”.

In the new movie, directed by JA Bayona and co-starring Felicity Jones and Liam Neeson, Weaver plays a woman whose adult daughter is dying of cancer; an unsympathetic figure, at least as she is seen through the eyes of her grandson. It is a fairytale of sorts, what Weaver calls “a unique blend of allegory and harsh, harsh reality”, and one that, in the context of her career in sci-fi and dystopian drama, is in some ways the most frightening landscape of all. A Monster Calls covers the triptych of worst nightmares: of a child losing a parent; of dying oneself and orphaning one’s children; and, the worst of all, suffered by Weaver’s character (and the thing that makes her tight-lipped demeanour so interesting), that of losing one’s child. “It’s not that she’s cold – it’s that she’s not sharing, because she can’t,” she says.

The film is set in England, and for reference Weaver drew on her own mother, born and raised in Essex, a graduate of Rada and the West End stage before she emigrated to New York and met Weaver’s television producer father. “She had the most beautiful speaking voice,” she says. “When I began shooting, I sometimes sounded like her. I really was uncomfortable. And I really needed to find the grandmother’s accent. It’s not a Manchester accent, but we didn’t want to be posh.” (The class setting is one of the few aspects of the film that doesn’t quite add up, though the film’s dream-like texture largely forgives it.)

In new film A Monster Calls. Photograph: Quim Vives

She is sentimental about England. To her regret, her mother appeared to lose all interest in her origins after emigrating. “She became, in her own strange way, very American – she was always very athletic and independent. I look back and think, ‘Why didn’t Mummy and I go on some wonderful tour of England?’ But she wasn’t interested. And she felt that, after the war, everything had changed. I think she didn’t want to be torn. It was easier for her to become an American citizen and have horrible American children.” She laughs. “We never did go on that tour. Too bad.”

Her mother was also unenthusiastic about her daughter’s desire to become an actor, mainly because she thought Weaver too sensitive to criticism (and then, of course, there was her height). Looking back, Weaver is inclined to be generous. “Do any parents want their daughters to be actors?” she says. “They were probably sceptical, but not unsupportive.” In any case, she believes that having curtailed expectations turned out to be a good thing; it allowed her to look beyond the obvious career plan.

In The Ice Storm in 1997. Photograph: Allstar/Cinetext/20th Century Fox

After graduating from Yale School of Drama, where she studied acting alongside Meryl Streep, Weaver only hoped she’d find work. “I was not a confident person, but I knew what I didn’t want to do. I didn’t want security, I didn’t want continuity. I had been discouraged at drama school from a career, so I thought, fine, I don’t care. I will just try in my own way. I really wanted to be a repertory theatre actor, because rep was still in existence in America, but only in a few places, like the Guthrie in Minneapolis. I thought, I’ll play big parts and small parts, and comedies and dramas, and I’ll mix it up myself.”

She had no model for this, and in fact thinks “models are probably dangerous for any woman starting a career”. Money, beyond necessity, was of no interest and fame was so distant a possibility as to be laughable. She smiles. “My only goal, frankly, was to be someone people wanted to work with again.”

The night before our interview, Weaver had dinner in New York with James Cameron, an early prep meeting for the three Avatar sequels he is writing and directing, and in which she will play a different character from the original. (Grace, the exobiologist she played in the first Avatar, died at the end of the movie.) Two of the three films will be shot at once, a stunning workload at a point in Weaver’s career when she might least have expected it. “I feel like knocking on wood,” she says. “I think things must be getting better. I think, finally, there’s a perception that the world is populated with both sexes, and there are all these lopsided projects in script form that need more oestrogen.”

This may be true. But the appetite for seeing older women on screen, particularly those who don’t take steps to disguise their age, isn’t one studio executives appear to have in abundance. “The thing is, I was never… I played a few pretty people, but that wasn’t what I was about,” Weaver says. “So I feel it’s a more interesting canvas now. If you think of Lucian Freud’s paintings, for example, the reason you look at those subjects is because they’re so revealed. And if this is my instrument, then in a way this gives me a more interesting canvas. As I watch movies or TV shows, I’m not sitting there going, ‘Oh, she looks like shit.’ Because that’s not the point. When I see wonderful older actors like John Hurt, I love how they look, and they haven’t tried to change any of that.”

She recoils from the idea that every actress has a “bad decade”, one when she skips, overnight, from playing the love interest to the mother. “Only if you believe the publicity, if you believe there’s going to be a period of time when you’re not going to get work. Of course, there’s this perspective that when you turn 40, you won’t get as much work. But I think television has changed that, because it has such strong female roles. And I’m a weird duck, because I was never a ‘girlfriend’. I was always too tall to be the girlfriend. So I didn’t have to say goodbye to my sexual self and hello to my executive self. There aren’t as many women’s roles as men’s, but I’ve never envied men their roles. Women’s are more interesting.”

In Alien 3 in 1992. Photograph: Everett/Rex/Shutterstock

This was the attitude she carried, at the age of 28, into what sounded like a dingy sci-fi movie called Alien, shooting in England. Although the script was good, on paper the role of Ripley didn’t look like a breakthrough part, nor Weaver a breakthrough player. Her parents certainly didn’t think so. “They both thought that I might be eaten alive. I was tall and galumphing around, and I don’t think they looked at me and thought, ‘A star in the making.’”

It was 1978 and Weaver had been living in New York, sharing a flat with a friend and earning a pittance through small film and TV parts. When she reached England, things didn’t look up. “I ended up renting, by mistake, an apartment on a square with a pub on each corner, so they were all yelling goodnight to each other all night.” She did what people under 30 from nice families do: she called her parents. “And I said, ‘I’m already shooting and I don’t know what to do, I can’t live here.’ And they flew over and found me a very quiet apartment off Sloane Square. I was so grateful. They were kind of British parents, you know? Go have a bash.” Not fussy Americans? “No,” even if in this particular instance they leapt to her aid like a thousand helicopter parents to follow. “I wasn’t a kid, but I was grateful. Sometimes you need your parents.”

Almost 40 years and three, nearly four sequels later, it is hard to imagine Weaver the ingenue, left to fend for herself by the studio. They didn’t look after her at all? “Oh, God, no! I was grateful I even got a car to Shepperton, which I shared with Harry Dean Stanton [who played Brett]. He was toking up every morning. I’d say, can we open a window? I don’t really do well with marijuana.”

When the film became a hit, the response of her parents, everyone she knew, and Weaver herself, was one of “utter shock and surprise” – and that has been her attitude to the fame side of things ever since. More iconic roles followed, in Ghostbusters, Aliens, Working Girl, a film in which Weaver plays a bent-out-of-shape female executive, all hard edges to Melanie Griffith’s curves and whispery voice, in a script that now looks pretty reactionary. Weaver won’t allow this: “I didn’t ever feel I was playing those things. I was playing a very specific person, who I knew, and who was impressive and someone who liked herself.” Although, she adds, “Playing Katharine was the only time I remember feeling that people might not want to have lunch with me.”

Wow.

“Isn’t it weird? They weren’t sure whether I was like Katharine or not.”

And they were afraid she was too much of a ballbreaker?

“She’s a very strong character. I also had a lot of women coming up to me at airports and saying ‘She [Griffith’s character] borrowed your clothes and took your boyfriend!’ They were very pro-Katharine.” Yet Katharine gets crucified at the end of the movie, dumped, fired and defeated in a way that Weaver admits she finds vaguely shocking. “I remember that last scene when Katharine loses and I think, until I played it, I hadn’t dealt with the idea she could lose. Aren’t I going to get the guy?”

With Melanie Griffith and Harrison Ford in 1988’s Working Girl. Photograph: 20th Century Fox/Everett/Rex

Weaver’s 26-year-old daughter Charlotte, who is at graduate school in California and wants to be a writer, only very recently saw Working Girl: “She just loved it. ‘Cool character, Mom.’” As a rule, the public aspect of Weaver’s career is something she has worked hard to keep out of the home. For a long time, her husband Jim Simpson ran a low-budget theatre (he is now a theatre and film director), which allowed him to be home for their daughter, while Weaver travelled and brought in the cash. A key to her success, she says, is “to have a very bourgeois life”, a stable home with one parent always in it – although she did suffer a crisis of confidence when it came to filming Avatar in New Zealand, when her daughter was in her teens. “I have only the one child, so I’m probably too clingy. I always have to discipline myself. Because you’ve got to let them go.”

Her own mother, she says, was not like this. “But I’m kind of a gooey… I don’t know why I don’t drive my daughter absolutely crazy, but she couldn’t be sweeter. She seems very nice about the fact that I’m very attached to her. We never went through that period of not getting along. I kept expecting it. Maybe she thought I was so attached that I’d become too pathetic.”

Weaver’s husband, meanwhile, has been understanding of her higher profile, unusually for a man of his generation, perhaps. But she says he was raised by a strong mother and was only ever grateful “that one of us could make a living. And in terms of what he’s given me, it’s priceless. If I didn’t have such a supportive husband, I couldn’t have done it. As it was, I did about one project a year. But I wouldn’t have been able to do that.”

In Alien: Resurrection in 1997. Photograph: Rex/Shutterstock

She is good at downtime. She loves living in New York and although she can’t take the subway – “the selfies and everything” – on the street, “I can just whizz along like Harry Potter in his invisibility cloak.” She loves “being part of the fabric of the city” so much that it can be a wrench to leave. “I still find it very difficult to be taken out of my little pond and go off and play someone else.”

One project that Weaver recently said yes to, rather surprisingly, was a cameo in the long-running ITV comedy drama Doc Martin. Selena Cadell, who plays Mrs Tishell in the show, is an old friend and would often tell her how fun the filming was. “I thought it was some sort of detective series. And then I was on Jonathan Ross with Martin Clunes – he’s so funny, such a lovely guy – and I had a drink with him and gushed away, and out of the blue they wrote this obnoxious part for me. I was thrilled.”

With Martin Clunes in the TV series Doc Martin. Photograph: ITV

Wasn’t she tempted to play the movie star card and say, “I’m sorry, I’m just too big for this”?

She looks horrified. “I can’t think of anything more awful. I don’t even know what that means. I don’t mind playing a person like that – I’m asked to play awful people all the time. But, to me, I’m still about eight years old. I’m a kid in a candy store. And to be part of the Doc Martin family for a week was a joy. I’m so jealous of British people. To hear about Martin’s life, with his livestock, spending the day with all these beautiful cows and sheep and horses. That’s the life.

“And to drive to Cornwall? So beautiful. Dorset and Devon. I’m just agog when I see the British countryside. Considering how many people there are and what an old country you are, you’ve managed to maintain such beauty and you’ve contained your sprawl. You’re all on the same page about the environment. And you all appreciate beauty and gardens and all these things. We have not been as successful.”

It’s a more optimistic view of Britain than is held by anyone who currently lives there, I say. Weaver laughs and suggests, “Prime minister May? All this stuff had to come out, but what’s so interesting is that there was so much passion against the EU. I don’t think anyone picked up on that. No one made any kind of argument about what the EU was giving you, only what it had taken away. Those arguments weren’t made.”

Our interview takes place before the US election, when it still seems likely that Hillary Clinton will win, something Weaver feels passionate about. “It’s shameful that we haven’t had a woman president,” she says, and the talk turns to the ugly mood on social media, not least surrounding the release of the all-female Ghostbusters reboot, a peculiar lightning rod for misogyny. “I was shocked,” Weaver says. “I still am. I read recently that the film hadn’t done well, and I wondered if the backlash online had been distracting for people. I enjoyed it very much.

In Ghostbusters in 1984. Photograph: Allstar/Columbia

“I love those women and I was sorry that happened. But I think there’s so much misogyny in the political atmosphere this year. I can’t remember anything like it. It’s like this last gasp of get-back-in-the-kitchen. I don’t know what it’s about, but I know it’s the end of it, the dying groan of the species going extinct.” This optimism, in hindsight, now looks tragically premature.

Weaver had her own brief brush with targeted online campaigning earlier this year, when the synopsis for Tomboy, a forthcoming movie that was later renamed [re]Assignment, was criticised by some as transphobic. The movie co-stars Michelle Rodriguez and tells the story of a surgeon who performs a gender reassignment operation against the will of the patient, a form of mutilation that was taken as a critique of the surgery in general.

Weaver says: “I can understand that. I can see that you could think we’re just trying to exploit this and make a movie about it. I play a very unsavoury woman who kidnaps Michelle Rodriguez, who is a guy, and turns her into a woman. And we certainly approached it with great sensitivity, about this kind of transformation. Walter Hill [the writer-director] was one of the original writers and producers of Alien, and I have always wanted to work with him again – he’s a master of the cinema. It’s a film noir. All I hope is people have an open mind about it.” In advance of shooting, Weaver says she met a “woman who was a transsexual and had some long talks with her about it, because she was worried. I very much tried to bring that energy in with me.” But again, the bottom line is, “You have to be able to tell a story.”

Photograph: Jody Rogac for the Guardian. Stylist: Emily Barnes. Hair: Rebekah Forecast, both at the Wall Group. Makeup: Sally Harlor. Clothes: Halston Heritage. Earrings: Robert Lee Morris

Never more so than now. Weaver tries to avoid spending too much time online. “I don’t go looking for trouble, don’t Google myself looking for horrible pictures. I admire people who can make all that part of their careers, and I know there are people at my agency who feel that’s very important. But I have enough to do.”

The prospect of spending many hours with James Cameron on Avatar may strike some as less than ideal, but Weaver says that, in spite of his tyrannical reputation, they have always had a good relationship. “He is a toughie when it comes to shooting. I was reading somewhere that he’s called Mij. Jim is charming, he’s a good guy. And very caring. And then, on set, he can become Mij – which is Jim spelled backwards – who is a different person, making terrible caustic remarks about everybody. The focus puller, or whatever. Never about actors. He’s very kind to us. It may be the one skill he doesn’t feel he has. Everything else, he can do.”

What does she do in the face of caustic remarks towards others? Weaver puts on her best head girl smile. “Not to sound like a Pollyanna, but I’d say, ‘You know what? When you say that to one person, you say that to all of us. We all feel like shit. I would encourage you to remember creativity thrives in an atmosphere of love, and don’t do that.’”

Weaver is so disarmingly sane, it is hard to imagine where her actor’s insecurity lies. But it is there, she says, in the way she worries and frets before the start of every film. You might imagine, with the new Alien, as with the Avatar sequels, that she could rock up on day one, safe in the knowledge that she did all the prep years ago. No, she says. “I wish I felt that way. That’s such a secure person who does that. I think there’s a mechanism in the actor that doesn’t allow you to feel that way, because you have to approach each one from a completely fresh perspective. That’s sort of the fun of it. Otherwise, why bother?”

• A Monster Calls goes on general release on 1 January.