She's an award-winning novelist, a TED talk sensation and Beyoncé's favourite feminist. But Chimamanda Ngozi Adichie has many more stories to tell, as Erica Wagner discovered in the April 2015 issue of Vogue - still downloadable here.

I'M on the shore of Lagos Lagoon with Chimamanda Ngozi Adichie on a late afternoon in January. It is harmattan season, when a hot wind blows across the Sahara, bringing dust that makes the sun glow dark gold as it hangs over the palm trees on the opposite shore. Adichie, in a neat-waisted patterned dress and teetering lavender heels that are utterly unsuited to the sandy ground, is about to pose for Vogue's photographer; but as we climb out of her car she asks me what I think of Lagos. She has just discovered that this is my first visit to Africa - and she's thrilled that my baptism takes place in her native Nigeria ("Not bloody Kenya!" she said, laughing, as we drove). What can I say? That I'm overwhelmed: by the pell-mell energy of the place, the urge to get on, to get ahead that you can feel in every encounter. But I'm overwhelmed, too, by the way in which, in the space of a single day, I've been drawn into the embrace of Adichie's life here, eating her food, meeting her parents, laughing with her friends, lounging on her sofa, talking about feminism, literature, our favourite TV shows, the fact that we both adore orange nail polish and are thrilled to discover we happen to be wearing the very same shade on our toes. Snap!

Chimamanda Ngozi Adichie was 26 when she published her first novel, Purple Hibiscus, which was shortlisted for the Orange Prize for Fiction and won the Commonwealth Writers' Prize. The books that followed, Half of a Yellow Sun - set during the Biafran conflict in Nigeria, a decade before she was born - and Americanah, a modern love story set between America and Nigeria, have also been garlanded with international prizes and critical praise. Salman Rushdie remembers meeting her at a PEN literary festival in New York, not long after Purple Hibiscus was published: "She did a one-on-one conversation with Michael Ondaatje in a packed auditorium at Hunter College. At that time she was just out of the egg, so to speak, and it was plain that she hugely admired Ondaatje, but what was so striking was her own confidence and authority. She very much held her own, and spoke fluently and powerfully, and all of us there that day could see that someone very remarkable had just arrived. A star is born, I remember thinking, and so it was."

My family says, 'Oh, you're such a man!' But I don't see why I shouldn't speak my mind

Indeed it was, and her stellar qualities would go on to find her an extraordinarily wide and diverse audience. Her 2009 TED talk, "The Danger of a Single Story", has had - wait for it - more than eight million views; it is a sophisticated yet charming and accessible essay on how we might see the world through another's eyes. But that viral explosion is nothing compared with what happened to the talk Adichie gave in 2013 at TEDxEuston, a series of talks in London focusing on African affairs. Entitled "We Should All Be Feminists", the speech, which addressed a feminism beyond race or class, took on a very different life. Before she had realised the impact her words were having, she got a call from Beyoncé, who eventually sampled the talk in "Flawless", a song on the eponymous album she released, to the world's surprise, on iTunes that December: it reached the top of the iTunes charts in 104 countries and sold nearly 850,000 copies in three days. Beyoncé first discovered Chimamanda when she came across her talk online. "I was immediately drawn to her," says Beyoncé. "She was elegant and her words were powerful and honest. Her definition of a feminist described my own feeling: equality of the sexes as it pertains to human rights, equal pay and sexuality. She called the men in her family feminists, too, because they acknowledged the need for equality."

Adichie insists - and I believe her - that she was taken aback by the success of both of those talks which, it could be argued, changed her from a successful author into a celebrity, although "celebrity" is a concept she clearly distrusts. "The things I think will do really well are not the things that do really well," she says, laughing. You might guess from looking at photographs of her that she is a very serious person, but her laughter comes easily and often. She said yes to the 2013 TED invitation mainly because it was organised by her brother, Chuks, who works in information technology and development, and she wanted to help him out. "But I thought, I don't have anything to talk about. I'm not the kind of person who can manufacture things when I don't care deeply about them. But my brother said, well, there is this one thing you give us endless lectures about…" A mock-serious look crosses her face. "Because it's known in my family, you don't want to demean women in my presence! And I knew this wasn't a comfortable subject, particularly for the people I was addressing, an African audience.

"I was still writing it when I went up to speak, and afterwards, clearly people had listened, clearly people felt strongly about it - but I let it go. So they put it online, and only then I heard about people using it in their classes, about people arguing about it at work and school." But the approach from Beyoncé was unexpected. The collaboration is not something Adichie has discussed much, wary that too much talk of pop music would shift the focus away from what she cares about. "I am a person who writes and tells stories. That's what I want to talk about. There's an obsession with celebrity that I have never had. But the one thing I will say is that I really do think Beyoncé is a force for good, as much as celebrity things go. I know there has been lot of talk in the past year about how feminism is 'cool' now, but I think if we are honest, it's not a subject that's easy. She didn't have to do this, she could have taken on, I don't know, world peace. Or nothing at all. And I realise that so many young people in our celebrity-obsessed world, well, suddenly they are thinking about this. And that's a wonderful thing. So I don't have any reservations about having said yes."

Feminism - gender equality - is a cause she cares about passionately. You don't have to spend long in Nigeria to witness the deeply patriarchal nature of the culture, where men are always greeted as "sir" and women are lucky to be greeted at all. But Adichie was brought up in a progressive household. Born in 1977 in eastern Nigeria, she grew up in Nsukka, a university town. That part of the country is still, she says, the place where her soul is most at home; she dreams of having a farm there one day. Her father, James, was professor of statistics and, later, vice-chancellor at the University of Nigeria; Grace, her mother, was the university's first female registrar - no small achievement. As it happens, her parents were staying with her when we met, in the beautiful stone-floored house she built about a year ago. Married 51 years, they have a pride in their daughter that shines in their faces, as does her love for them. Right from the beginning, her books were distinguished by strong female voices: Kambili in Purple Hibiscus, Olanna in Half of a Yellow Sun, Ifemelu in Americanah.

The oppression of women, she says, "Makes me angry. I can't not be angry. I don't know how you can just be calm. My family says to me, 'Oh, you're such a man!' - you know, very lovingly… But of course I'm not, I just don't see why I shouldn't speak my mind." She got into trouble for speaking her mind in Nigeria: when an interviewer addressed her as Mrs Chimamanda Adichie, she corrected him, saying she wished to be known as "Ms", which the journalist reported as "Miss". Her insistence on her own family name was all over the news here last spring. She should be happy to be addressed as "Mrs", she was told, since she was, after all, married. She laughs now, but it's clear the story still disturbs her. "It was the lack of gratitude on my part for having a husband. And yet I didn't want to proclaim it: I wanted to claim my own name."

Nigerians need to make a space for dreaminess. But life is short

Her husband, Dr Ivara Esege, is assistant professor of family medicine at the University of Maryland, in Baltimore. They have a house in Columbia, outside the city, in what Adichie calls "a really mixed neighbourhood. In the US, 'mixed neighbourhood' usually means two black people, but this is really mixed: Africans, African-Americans, people from everywhere." Here in her house in Lagos there's a photograph of him as a little boy on a bookshelf, and one of Adichie at about the same age just below. Although she's not comfortable bringing him into the conversation, occasionally she lets something slip, like telling me about a pack of crayons he gave her recently. Crayons?

"I do all these drawings for my clothes," she says. "Really terrible drawings. But I love to do them, and he gave me the crayons so I could add a little bit of colour." It's clear that Adichie sees no contradiction in being a woman of fashion and a feminist. The dress she wears for the shoot is one she designed herself; she works with local tailors to have her designs brought to life.

In the middle of the day we eat a wonderful lunch prepared by Mr Taiwo, her cook: jollof rice, vegetable soup, roasted chicken, moin-moin (a savoury cake of black-eyed peas, which Adichie especially loves) and garri, a Nigerian staple that she really doesn't love but wanted me to try. Her family, she says, tease her about her dislike of it. She mimics them: "'Oh, you say you are such a proud Nigerian! But how can you be if you don't like this?'" She throws back her head and laughs. (It clearly is quite a big deal, this: she wrote a piece about it for The New Yorker a few years ago. I confess, I didn't adore it either. Made from pounded cassava root, it's like really, really dense school mash.)

After we finish, Adichie's favourite make-up artist, Stella, arrives to get her ready for the photographs. Having a make-up artist come to your house is more common in Lagos than it might be in London, but it took Adichie a while to find someone who would give her the natural style she prefers - a lot of Lagos make-up is pretty dramatic. "Why pay for it if you can't see it? That's the thinking!" Adichie says, laughing again.

Stella, a tall, elegant woman in a long black dress and silver bangles, highlights Adichie's truly extraordinary beauty perfectly, a shimmering gold on her eyelids the only really glossy touch. Adichie suggests I might like a go in the make-up chair, but Stella doesn't have with her the right shade of foundation for me. This, of course, is the experience many women of colour have in Europe. "Oh, yes," Adichie shrugs. "I always carry my own base with me."

© Akintunde Akinleye

Talking about race with Adichie is fascinating. "I only became black when I came to America," she writes in Americanah; her character Ifemelu's experience is drawn from her own. "In Nigeria I'm not black," she says simply. "We don't do race in Nigeria. We do ethnicity a lot, but not race. My friends here don't really get it. Some of them sound like white Southerners from 1940. They say, 'Why are black people complaining about race? Racism doesn't exist!' It's just not a part of their existence." But it has been part of hers in America, where her experience "is always shaped by race. Somebody sends a limo to pick me up, and I just notice an attitude that the white, older male driver has. He's thinking, that's who I'm picking up? And I can't help thinking, if I were white, would he have a problem? If I were black and male, would he have a problem?" She has focused her attention on gender inequality because here in Nigeria, that's her primary experience of inequality. In Nigeria she would know why a driver would have a problem with her: "Because I'm a woman."

But all the same, she says she was "personally furious" that Ava DuVernay's film about the American civil rights marches, Selma, was almost entirely overlooked by the Oscars. "I took that very personally. It's almost a slap in the face for a person who wants to believe in some kind of progress; 2014 was such a difficult year for America and race." She doesn't even have to mention the riots in Ferguson, Missouri, following the shooting of Michael Brown by the police, or the death of Eric Garner in New York, and the protests that followed; those events hang in the air between us. "Even when I'm not in the US, I follow what's going on, I'm very emotionally invested. And I find myself thinking that maybe I'll write an essay about it: looking at the idea that there's something similar in the way that American society looks at black men who commit crime and women of any colour who report a rape. And I think the similarity is that you are expected to be perfect and pure before you can get any sympathy, any human empathy. 'Well, the kid stole cigarettes, so he asked for it, right?'" Brown was alleged to have stolen abox of cigarettes. "Like, 'Well, she wore a short skirt.' It's so ugly. And with the film of Half of a Yellow Sun - I remember Thandie Newton saying to me that it was important to her because you don't usually get to see black love on the screen this way."

She had almost no involvement with the film "because my book means so much to me", but she was pleased with it, despite the fact that it was a small production. "It was very indie; they shot it in 12 days or something. I sometimes imagine what it would have been if it had been a grand production. But I do think it's a film that was lovingly done." As, doubtless, Americanah will be: optioned by Brad Pitt's company Plan B, it is to star Lupita Nyong'o, the Mexican-Kenyan actress from 12 Years a Slave, for whom Adichie "writes with the voice of a modern Africa, where ideas of tradition and modernity interact… She is witty, frank and compassionate, and her writing feels timeless and contemporary at once." Nyong'o was an admirer of Adichie's books long before she was cast in Americanah: "For the first time I felt that someone had found the words to express sentiments, analyse situations about the rich and varied African immigrant experience, in a way I never could."

Adichie's novels and stories, for those who have yet to discover them, strike a delicate balance. Yes, they deal with pressing political issues of gender and race. But they are voluptuously, deliciously readable, too, and charming and funny and smart. And they are part of a wave of remarkable writing from the African continent: work by authors such as NoViolet Bulawayo, Dinaw Mengestu, Taiye Selasi, Teju Cole and many others is creating a truly global literature. But it's recognition in Europe and America that brings such authors real success, and some have argued that this is, in itself, a new expression of colonialism. Adichie dismisses this: "We can either have a conversation about making 'Africa' some exclusive, bad space, or we can have a larger conversation about the publishing world. It's just a question of power and money and infrastructure, rather than one of Africans being self-hating or something."

Her writing feels timeless and contemporary at once

She herself is proving to be a major force in the development of local authors: for the past eight summers she and her Nigerian publisher have hosted a writing workshop in Lagos. These days there are 2,000 applicants for 20 places - she wants to keep it small, "otherwise it loses something". It's clear that this is a project dear to her heart: she loves teaching, she says. "I want to make it valid, to dream about books and writing. Because in Nigeria it's very hard; people will say to you, what do you mean, 'writing'? Nigerians are a very, very practical people. And while I admire practicality, I feel we need to make a space for dreaminess. But life is short. I'll say, don't give up your job. Get up earlier, make the space. If it matters to you, make it matter. I wrote Purple Hibiscus when I was an undergraduate. I was my sister's unpaid housekeeper, I was cooking, taking care of my nephew - I got up at 2am to write." In her company you can almost see her at work: before supper we stopped for a smoothie in a local bar and gallery with one of her best friends, Chioma, and I watched Adichie's face as Chioma told a startling story about an encounter she'd had at work. Adichie took it in the way that real writers do, storing everything away carefully in preparation for eventual transformation into fiction. It was quite something to see. But no, she won't reveal anything about her next project. When I ask if she'll tell me what she's working on now, she shakes her head firmly: "I can't!"

To spend time in Lagos with Chimamanda Ngozi Adichie, to stand on the shore of the lagoon as she poses, laughing, for Vogue's photographer, to drive through the city's crowded roads, to share a drink with her and her friends, was very special. But for all her fame and success, she remains down-to-earth. When I ask her if she sees herself as a feminist heroine, she looks puzzled. Her heroines, she says, are "the nameless women in the market, who are holding their families together. They are traders and their husbands are out drinking somewhere... It's those women I admire. I am full of admiration for them."

Read more: Inside April Vogue