Cara Delevingne is sandwiched between two cushions on a leather sofa, describing her latest project - surprisingly, a young-adult novel - and blinking back the tears as she recalls the exhumation of her painful teenage years required to write it.
By this point our interview, in the office-slash-props cupboard of a photography studio in Hollywood, has begun to feel more of an emotional exorcism, both of her own past and the empathic bond she feels with the teenage portion of her 40.6 million Instagram followers, to whom the book, Mirror, Mirror, is an offering.
"I still talk to this one girl on Instagram who was so close to committing suicide because both of her parents died of cancer a year apart," she says.
"I said, 'Please listen to me when I say don't do it. Just walk away. I know exactly how you're feeling. You're standing at the f???ing edge, about to throw everything away. But what you don't understand is that if you don't throw it away, you can help others.' When I connect with people like that, I can honestly say that I've been there."
In fact, Cara has been there twice. Most recently in 2014 when, at just 22 years old and having become the most obsessed-over model of the digital age - winning Model of the Year at the British Fashion Awards for the second time, and with campaigns for Burberry, Chanel, Mulberry and Topshop under her belt - she found her stellar career interrupted by a bout of severe depression, a recurrence of an earlier episode at the age of 15.
Like the first incident, it brought her to the brink of suicide, but most of the world was too busy fetishising her eyebrows to notice.
With Karl Lagerfeld presenting a Chanel collection, Paris, 2014. Photo: Alamy Stock Photo
That second episode was assuaged in part by writing songs and poetry during an emergency break in LA.
"Writing came from that lost feeling, that alone feeling," Cara admits. "Because at that moment in time you don't know how else to light a candle in that dark place. But when you do, you let it pour out."
And so the idea of writing a novel slowly began to form in the back of her mind. "That's how I realised that it might help others," she muses, still emotional. Later, she adds, "If I don't tell them [my followers] the truth about myself, then why the f??? am I here?"
I first met Cara in 2013 at the Cannes Film Festival, when she was a world-famous model but acting novice, having only appeared in a cameo role in Joe Wright's Anna Karenina. She tagged along with my group to a function held by a prominent fashion designer and revealed herself as a charming goofball, all kittenish tomfoolery.
So it is strange to hear her now, barely 25, talk as a seasoned counsellor to Generation Z. Though, to be fair, she has devoured several lifetimes in that short period.
Since taking up acting, she has already starred in a blockbuster (Suicide Squad); worked with some of the most revered actors and screenwriters in the industry, among them Judi Dench and Tom Stoppard (for Tulip Fever); played a female lead (in Paper Towns); and she secured top spot in The Hollywood Reporter's chart of most popular actors (based on data from social-media websites) in August. She has also spent months walking red carpets to promote the sci-fi film Valerian and the City of a Thousand Planets, her head shaved and wearing futuristic silver creations.
At the Cannes Film Festival, 2013. Photo: Alamy Stock Photo
Today, however, she looks more of a cross between Tank Girl and Andy Warhol muse Edie Sedgwick, a cocktail of self-assertion and vulnerability, in a white vest top that exposes her tattoos.
Without her old veil of blonde hair, she looks tougher but feels more "exposed", which is, she says, "liberating". She shaved it off for her upcoming film Life in a Year, in which she plays a teenage cancer patient.
It was while she was on set in Toronto earlier this year that Cara began to feel the gloom descend. "It really put me back into a dark place," she says. "I felt like a moody, hormonal teenager again. That's probably when I thought about death the most."
What helped her was channelling her demons into Mirror, Mirror, which she worked on in her downtime in conjunction with UK-based novelist Rowan Coleman, with emails "flying back and forth across the Atlantic". The nine-month co-writing process was, says Cara, life altering.
It would be easy to be sceptical of her true input into Mirror, Mirror but her publisher Anna Valentine, who has previously worked on books by Russell Brand and Justin Bieber, insists: "Cara had a very clear idea about the story she wanted to tell, and Rowan helped to bring [it] to life."
For her first meeting with Coleman in November 2016, Cara turned up armed with poems she had written as a teenager, ideas for themes, embryonic characters and "nuggets" of the initial premise, which the pair teased into fuller storylines. "You're trying to cram in all these puzzle pieces," says Cara. "But what you need to do is take a step back. Tear it apart, but not throw anything away."
She was firm that her first novel should not be set in the "fashion bubble" but focus on the lives of ordinary teenagers: "I thought, 'Let's get down to the real shit, shall we?' " Described as a "twisty coming-of-age story", Mirror, Mirror is dark and gritty (and, it should be said, sweary). Set in south London in a fast-paced world of Snapchat threads - all "KK"s and "FFS"s - it explores the effects of growing up in the digital age, something Cara feels fortunate to have narrowly missed out on.
"I always felt as a teenager that everything I did was because I wanted someone to love me. I think the added pressure of social media would have destroyed me. I was already on the verge of being destroyed anyway."
Cara's background is ostensibly one of extreme privilege. She grew up with her two older sisters Chloe, 32, and Poppy, 31, in the wealthy London district of Belgravia. Her father, property developer Charles Delevingne, is the grandson of Viscount Hamar Greenwood, the last chief secretary for Ireland, and his paternal aunt was 1930s society girl Doris Delevingne, an intimate of Sir Winston Churchill.
Cara's mother Pandora, a former model whose mother was lady-inwaiting to Princess Margaret, is also a renowned socialite, so an inevitable path of horsey events and summer balls lay ahead for the daughters.
Though an enviable family on the surface, behind closed doors Pandora, whose disabled brother Rupert died when he was 22, struggled with addiction to prescription medicines and heroin and was later diagnosed with bipolar disorder.
Often absent from the family home, Pandora spent time in clinics or stayed with family friend John Aspinall. By the time she was eight Cara was nicknamed "Monster", a free spirit who ran wild either naked or in a Spider-Man costume. She also stopped eating for a period, effectively a hunger strike.
She struggled with reading and was diagnosed with dyspraxia, which affects co-ordination, but took up drumming and developed an aptitude for role-play
There were always moments when I was shifting, adapting into the different people I needed to be for someone else. To be a caretaker [was one]. Growing up, I was definitely good at lying. That was a mechanism, a way of living." Then, at 15, Cara discovered the truth about her mother's addiction. "It was like having a bomb [dropped], suddenly being aware."
She began to self-harm - running into trees to knock herself out or scratching herself until she bled. "I did it to scratch the surface of what the pain is like on the inside," she says. "The more and more pain you are inflicting on yourself, it's like: 'I can feel. I am alive.' "
Cara left school for a spell, recovering with psychiatric help and psychotropic drugs, before enrolling at a boarding school. But she doesn't blame anyone for her self-destructive tendencies.
"Obviously as a child, you see things, you learn behaviour by copying. But what the f??? would be the point of blaming my mother? My mother gave birth to me. To appreciate the life that someone has given you is more important than holding on to the bad things, and saying, 'She f???ed up my life.' It's my choice if I continue a pattern ??? or not."
Has she ever expressed anger towards her mother? "Of course. Thrashing around on drums, exploding, really helped. I'm still learning to be angry now. I don't get angry at people. I can just switch off. I can completely disassociate. I internalise it."
So is it possible to read her book as a fragmented mirror, and Red, the shaven-haired and tattooed narrator who is the drummer in a school band, as a reflection of her?
Her publishers are keen to stress that Mirror, Mirror is not autobiographical - and it is, clearly, a work of fiction - but Cara found the process cathartic.
"Sometimes when I write it's so brutally honest. I write so darkly," she says. "This is why writing is so therapeutic for me." Better than talking to a therapist? "Sometimes in therapy, you feel like a complete narcissist. You're already feeling depressed and so f???ing selfish because you can't stop thinking about yourself and how shit you are.
"I definitely think you can go to a therapist every week and just chat, gossip, and skim the surface of problems. Not go down deep and really gut the shit that's going on."
In Valerian and the City of a Thousand Planets, with Dane DeHaan. Photo: Supplied
Another subject at the heart of the book, and one that Cara was keen to explore, is sexuality; in particular, how her characters navigate the reactions of their parents and peers to their sexual orientation.
Cara herself fell in love with a girl when she was 20, and has since dated men, including singer Jake Bugg, and women, including actress Michelle Rodriguez. Most recently she was in a relationship with 35-year-old musician St Vincent, aka Annie Clark, for roughly 18 months.
In 2015, she declared to US Vogue: "I think that being in love with my girlfriend is a big part of why I'm feeling so happy with who I am these days. And for those words to come out of my mouth is actually a miracle."
"The beautiful thing about teenagers now is that they are able to be more open about things like sexuality," says Cara today. "Girls I have met who are 13, 14, 15 years old say, 'I don't know if I like guys or girls yet.' I was like, 'What? If I'd even had the concept of thinking that way when I was that young???' That inspired me." She adds: "I wanted to show the strength in that, how much that has changed."
In 2014, Cara left modelling behind for Hollywood - only three years after her big break in Burberry's 2011 spring/ summer campaign, and five years after she was first scouted and signed to Storm modelling agency by the same agent who discovered Kate Moss.
But she hasn't completely abandoned modelling. She still works occasionally for Dior and Chanel and recently teamed with Puma to create a documentary series about Girl Up, a United Nations campaign to empower young girls. Given that she doesn't need the money (her net worth has been estimated at $23 million), I can't help wondering why she does it.
"I actually really value that part of myself, but maybe that's just me being stuck," she explains of her complicated relationship with modelling. "That's me still wanting to be desired. And feeling like that's the only way that I am desired."
In the past, Cara has called fashion "a dysfunctional family". Today she says, "As a model, I played the part of what I thought society wanted me to be as a woman. That's why that part of modelling destroyed me.
But she is quick to add, "It wasn't fashion's fault. It was me getting successful from playing a part that then felt ??? not exactly not genuine, but this stereotypical idea of female beauty. What I saw as being feminine - that girlie, femme fatale, pretty lipstick-type girl."
Part of the problem appears to be that, despite seeming to be "besties" with nearly every celebrity, many of whom attended her birthday celebrations in Mexico in August, there have been times when Cara lacked deep emotional support. "I didn't have anyone around me that I felt I could tell, 'This is how I'm feeling.' "
She admits to a talent for hiding her emotions. "I'm good at 'I've just had a mental breakdown this morning, but I'm totally fine.' I'm not someone who cries there and then. I'll hold it in. Until I'm in the bathroom by myself."
So how has she dealt with her frantic schedule over the past six months without falling into her old patterns? The short answer: crying and yoga. "I have to cry every day. If I don't, I get angry. So when I go and see my [yoga] teacher, it's like I download all the pain that I've been holding on to. I cry and I shake. It's like a f???ing exorcism."
At the end of the interview, I am heartily embraced once, twice, three times. Then Cara chuckles and snaps into goofball mode again, threatening to lift me up and piggyback me down the studio stairs.
If this story has raised issues for you, call Lifeline: 13 11 14