Halloween is just around the corner, and it’s a safe bet that Stranger Things’s most recognisable character, Eleven, will be one of the most popular costume choices at house parties from Hackney to Harlem. It’s rare that a television character makes such a cultural impact as the enigmatic pre-teen with her shaved head, numerous telekinetic gifts and love of Eggos waffles, but even if you haven’t seen Millie Bobby Brown’s tremendous performance in the Netflix series itself, you’ll have seen the memes.

“I never thought this would happen… it’s a pinch-me moment,” says Brown, an elfin 12-year-old who greets me with a cheery hello as we meet in London’s Rosewood Hotel for what’s sure to be a long day of press. Dressed in a metallic Burberry shift dress and with her now pixie-cropped hair (it was shaved for the show) pinned neatly to one side, she’s polite, alert and chatty – and clearly having the time of her life. Less than a week prior to our meeting she was performing Uptown Funk at the Emmys with her Stranger Things co-stars, she's rapped Nicki Minaj's Monster on The Tonight Show Starring Jimmy Fallon, and she already boasts over a million Instagram followers. “I’ve watched the Emmys for almost my whole life so it was crazy to finally be there in the audience clapping and actually going on stage. Hopefully one day I’ll get to be actually nominated.”

With Stranger Things co-stars Gaten Matarazzo and Caleb McLaughlin. © Getty

It seems likely. Last month Business Insider reported that Stranger Things had 8.2 million viewers in the first 16 days since its July 2016 release - making it more popular than Narcos, Jessica Jones and even House of Cards. Set in smalltown Eighties Indiana, Stranger Things is a nostalgic, sci-fi drama based around a boy who mysteriously vanishes, and the quest his mother (played by a brilliant Winona Ryder) sets out on to find him. Paying homage to Eighties pop culture throughout, it has the warm, fuzzy, friendship-focused appeal of Stand By Me or ET - and Brown’s sensitive and mature portrayal of the mysterious Eleven, an escapee from a sinister government facility, is undeniably a large part of what has made it a cult hit. It has already been renewed for a second season in 2017, though Brown’s return is as yet unconfirmed (though surely, surely, they wouldn’t go on without her?). But how does a 12-year-old with relatively minimal acting experience come to give one of the performances of the year?

With Ryder in Stranger Things © Netflix

“The thing is, I get asked when I first knew I wanted to act so often, and I genuinely can’t answer it. It’s just… I got the bug and that’s it,” she says earnestly in clipped English (her American accent in the show was perfected after watching lots of television whilst living in Orlando). “I didn’t do school plays… I’ve never done a play in my life, actually. Not even a nativity. If I’d been in a school play I’d probably have sneezed and messed everything up. With Eleven it was about going by instinct – like what I’d do with her body language, and how she spoke. It was really fun to suggest things and embody the character myself.”

"I didn’t do school plays… I’ve never done a play in my life, actually."

Whilst talent seems to come very naturally to Brown, her big break was harder to come by. Born in Spain to British parents she has since lived for stints in both the UK and the US, getting small roles in NCIS, Modern Family and Grey’s Anatomy as well as a part in BBC America's Intruders. It has been reported that her family faced numerous financial difficulties in helping her pursue her career dreams, and they’re clearly never far from her side now that success has arrived. Her next appointment after meeting me is a period of “chill time” with her father, and she informs me that her mother is responsible for making sure she dresses “appropriately" for her age. When it comes to practising her lines, she turns to her father, who has “a great American accent and knows all of the characters”, whilst myriad family members manage her various social media accounts. 19-year-old brother Charlie looks after Twitter, 22-year-old sister Paige is in charge of Instagram, and an aunt runs her YouTube channel. “It’s really fun to have them along on the journey to experience things with me - I wouldn’t be here today without their support,” she says, big brown eyes widening for emphasis. “My parents are so amazing and they’ve travelled around the world with me. A lot of Eleven’s body language is from them – they’ve helped me a bunch.”

© Netflix

Brown is so eloquent and mature that it’s easy to forget that she’s only 12. One minute she’s intently describing precisely why she wants to work with Steven Spielberg and Jodie Foster in the future, and the next minute she’s reminding me that the reason she hasn’t watched many of Ryder’s films is because she’s too young and the age ratings too high. As I leave, a Netflix rep informs her that she’s due to get on a Eurostar to Paris with her Stranger Things co-stars that afternoon, and she asks excitedly: “Will it be just us kids, sat together? On a table, together?” She describes her fellow child actors Finn Wolfhard, Gaten Matarazzo, Caleb McLaughlin and Noah Schnapp as “big brothers”.

Automatically you worry that finding fame so quickly could be damaging to someone so young – it’s not like we haven’t seen it happen to her predecessors. Brown admits that she can count her friends “on one hand – you lose a lot of friends along the way,” but then those that she does have seem like permanent fixtures in her life. “My best friend Greer is not a well-known person but she is so talented. She’s actually a designer so I want her to design me something to wear one day. Then Maddie Ziegler, she’s in the business. So it’s really awesome to have friends who are there for me in LA,” she chatters on. “And then here in England I have a friend Salmara who I’ve known for most of my life. Even if you lose some friends, you make more.” There’s also clearly a lot to be said for having four castmates of a similar age – doing the press for the series as a group looks a lot more fun than it might be if she were on her own. And the industry has changed tremendously - the days of Judy Garland and Macaulay Culkin arguably being pushed to their limits are firmly in the past and have made way for a much more accommodating, considered approach to how to nurture child actors without demanding they instantly transform into mini-adults. Brown still seems very much a child, as she should.

© Netflix

In her own time she likes to watch Friday Night Lights and The Vampire Diaries, whilst her favourite films include the Twilight franchise and To Kill a Mockingbird (and wouldn’t she make the perfect Scout?). She also does Thai boxing every day, loves singing – see her YouTube account – and has recently got into rock climbing, though can’t do it when she’s filming. “Because I do it without a rope it’s extremely dangerous. If I broke my leg whilst we were filming I’m sure they’d KILL me!” Whilst she went to school when she was younger, Brown now has an online tutor – her favourite subjects are English literature and science.

She says she loves fashion but “hates” shopping. She names her favourite brands as Burberry, Stella McCartney and Coach, and sat front-row at the latter’s New York Fashion Week show alongside her “great friend” Winona Ryder. Not long after she hops on that Eurostar to Paris following our meeting, a picture turns up on Louis Vuitton's Instagram account showing her and her Stranger Things co-stars alongside the brand's creative director, Nicolas Ghesquière. Ghesquière shared a couple of pictures of himself with the cast too, hinting at "an exciting project coming up". Fashion, it seems, loves her too. However her mum chooses all of her outfits, she says, because: “I’m not a girly girl. I love wearing this stuff, but if it was my choice I’d come in in my tracksuit. But my mum’s like, ‘no, you put this on, you put that on…’” When I ask her what she would wear, given the choice, she tells me that she went to dinner in a Pikachu onesie last night.

© Louis Vuitton/Instagram

The pressing question, of course, if whether Brown will return for the second series of Stranger Things. When I ask her about the next step in her career she says that she’s “open-minded,” but solemnly reminds me that she’s “focusing on Stranger Things and Netflix right now”. Most revealingly of all, when I ask her about whether she’s planning to grow her hair out now, she says: “I don’t know if I’m growing it out just yet… To be honest I think if I do come back and I had to cut my hair again I’d be fine with it.”

Here’s hoping. But whatever happens, it’s clear that for Millie Bobby Brown, being Eleven has been the experience of a lifetime, and she’s making the most of it – as any 12-year-old would.

“I think the show’s success is because we have a great cast and a great crew. I kind of knew it would happen, that it would be big, because our writers are geniuses and we have a great cast. We’re like a family.”

With Ryder at the Coach spring/summer 2017 show in New York. © Getty

Season One of Stranger Things is on Netflix now.

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