She’s widely regarded as one of the world’s greatest living actresses, but Meryl Streep still fears failure.

When Liane Moriarty, the author of Big Little Lies, was tasked with creating a plot for a second season of the award-winning TV show based on her novel, she had just one request: “Get me Meryl Streep.” Liane had originally been against the idea of a second series; the first was based on the book and had been wrapped up in a perfect little ending. But then the characters of the Monterey five kept playing on her mind, and an entirely new character turned up: Mary Louise Wright, the mother of the slain Perry Wright. Liane’s sister told her that she could cast whomever she wanted, so why not pick her favourite actress for the new role? That actress was mega star Meryl Streep.

In a beautiful piece of symmetry, it would turn out that the character of Mary Louise would be perfect for Meryl. On June 22, 1949, when Meryl Streep was born, her birth name was not the famous moniker we know today. Instead, she was christened Mary Louise Streep, but along the way “Meryl” became her nickname and she stuck with it. When Liane Moriarty discovered this, she knew it was meant to be. And then it turned out that Meryl herself was such a fan of the series, she signed up immediately to season two before there was even a script to read. Of course, she is perfect in the series – she’s Meryl Streep, after all. Her name has been synonymous with acting perfection for more than 44 years. After the première of the new series in early June, one newspaper ran the headline: “Meryl Streep single-handedly justifies more Big Little Lies.” As if it would be any other way. It’s easy to imagine that the “Get me Meryl Streep” conversation is one that happens daily in Tinseltown. The actress, 70 this month, has received the most Academy Award nominations of any actor: 17 times for Best Actress and four times for Best Supporting (she has won three times). But interestingly enough, while casting Meryl is a sure-fire road to success, it’s the actress herself who takes the most convincing, every single time.

“Even though I’ve had a very long career, each character I play seems to me as important as, or more important than, the previous one,” she says. “I can’t help but start worrying about how I’m going to pull this off and I lose confidence in myself. And each time this happens, I tell my husband that I’m going to have to [tell] the producer that I can’t do the film after all.” She laughs to herself. “And each time my husband tells me he’s seen it all before and I never make that call.” Part of the fear, she says, comes from the expectations she places on herself. But another part is due to the extra drive it gives her. “Deep down, I think I do it on purpose. It’s part of my pattern, although I don’t want to admit that to myself. I have this need to feel overwhelmed by self-doubt in order to get me to invest myself fully into the role with the same intensity as before… I get scared that maybe this time I won’t be up to the task.” Perhaps part of this self-doubt stems from the early years in her career as well. While Meryl was a shining star as a drama student at Yale, it took a long time for her stage success to translate onto the big screen. On one of her very first movie auditions, for the lead role in King Kong, the director Dino De Laurentiis took one look at Meryl, then 31, and said to his son in Italian, “This is so ugly! Why do you bring me this?” Meryl also happened to speak Italian and replied to the director, “I’m very sorry that I’m not as beautiful as I should be but, you know. This is it. This is what you get.” She continued to work on Broadway before finally landing a role in the 1977 film Julia – it was a bit part, but it meant she starred alongside Jane Fonda, which was instrumental in Meryl’s career. Jane was 10 years older than Meryl and the younger actress took the opportunity to ask all the questions she needed answering: what did Jane do when she was nervous? How did she overcome fear? The lessons worked; since then, Meryl has credited Jane for “opening more doors than I probably even know about”. But before all that, it was her family that Meryl credits for having the biggest impact on her path to acting. Firstly, her grandmother provided the inspiration. “I realised I was born for this job when I started imitating my grandmother,” Meryl laughs. “I wanted to be like her and I put on make-up, putting wrinkles on my face to look like her. As a young girl I was constantly wondering: what would it be like to be this person or that?” And then it was her mother who gave Meryl the boost to give acting a go.

“My mentor was my mother,” Meryl says, “because she said to me, ‘Meryl, you’re capable… You can do whatever you put your mind to. If you’re lazy, you’re not going to get it done. But if you put your mind to it, you can do anything.’ And I believed her.” Eventually, the movie business realised what they were missing out on and Meryl exchanged Broadway for Hollywood. Robert De Niro, who had seen Meryl acting on stage, asked her to be cast as his girlfriend in The Deer Hunter in 1978 and she was nominated for her first Academy Award. One year later, she won the award for her role in Kramer vs Kramer, opposite Dustin Hoffman. And the momentum never slowed from there. The “over-40” cliff that a lot of talented actresses can fall off because the movie industry doesn’t know what to do with them, never happened to Meryl. In fact, it was one of the best jokes of the 2014 Golden Globes, when co-host Tina Fey said, “Meryl Streep is so brilliant in August: Osage County, proving that there are still great parts in Hollywood for Meryl Streeps over 60.” So what will the film world look like for Meryl Streeps over 70? Unsurprisingly, still quite stellar. She has another two movies out this year, including the remake of Little Women, in which she works alongside her Big Little Lies co-star Laura Dern. And then, for a total tone change, she’ll be starring in The Laundromat, based on the real life investigation of the Panama Papers in 2015. It will be released on Netflix later this year, the first time Meryl has done a project for the streaming giant, but probably not the last – she is extremely good at staying relevant in the fickle world of showbiz. Unlike many of her other A-list peers, she’s also very good at staying private in her personal life. In fact, you probably wouldn’t be able to name her husband offhand – despite the fact that they’ve been married for 41 years.

Don Gummer came into Meryl’s life on the heels of one of the worst things that had ever happened to her. In March 1978, the love of her young life, actor John Cazale, died from lung cancer, aged 42. The actors had been living together for three years before he was diagnosed with the terminal illness. John and Meryl had both been cast in The Deer Hunter, but John didn’t live long enough to see the final film. Meryl was just 29 at the time, and it is a loss that has stayed with her. “I didn’t get over it, I don’t want to get over it,” she says. “No matter what you do, the pain is always there in some recess of your mind, and it affects everything that happens afterwards. I think you can assimilate the pain and go on without making an obsession of it.” In the aftermath, she met Don, a friend of her brother’s, who lent her his apartment after John died and she needed somewhere to live. They fell in love, fast, and six months after they met, they married. Meryl describes Don as “the linchpin” of her life: “our marriage and our children, and their wellbeing, inform all the decisions we make.” A year after they married, she gave birth to their first child, before going on to have four children in total: Henry,Mamie, Grace and Louisa. Both Mamie and Grace followed in their mum’s footsteps and went into acting, but decided to keep their father’s name. Entering in the acting world with the surname Streep would, understandably, be quite an intimidating prospect.

Meryl and Don raised their family on a farm in Connecticut, far away from the bright lights of Hollywood. But being a mother has informed many of Meryl’s roles, not least her latest one in Big Little Lies. Coming into the show as the mother of the abusive Perry, the character of Mary Louise is definitely a wildcard. But the nuances of playing a mother grieving a troubled child is what drew Meryl to the part. “I’m playing someone who is dealing with whatever the deficits of her parenting were and the mysteries in that, and how you can’t go back in time and fix something,” she says. “All those issues, that was interesting to me. And it felt real, honest, honestly investigated… I felt like I had something to give to this piece.” Despite her constant self-doubt that every new role will be the one that breaks her, there is a level of passion for the work itself that keeps Meryl going. “I feel the same excitement and enthusiasm when I’m working today as when I started out. Every character that I play has the same importance as the first one I interpreted. Acting still gives me tremendous pleasure and I love my job as much as ever… I still feel this guilty pleasure when I start imagining myself in the life and feelings of a character.” Meryl also felt the underlying message of female empowerment was important to put her weight behind. “Look, women are free and more independent compared to whom? Forty thousand years ago, maybe. It’s a fairly recent emancipation,” she says drily. “We should be careful not to overestimate the actual freedom of women today… It’s still more difficult for women to achieve their goals and reach higher level positions in society than it is for men, although we are making progress. I remember when I was 20, my mother said to me, ‘Never learn to type, otherwise you will end up a secretary.’

“I still have vivid memories and impressions from when I was starting out that it was difficult for women to pursue their ambitions, and young women were constantly being valued much more for their beauty than for their intellect. We have to change that dynamic.” Big Little Lies, she says, is “a provocative act of emancipation and a reflection on male and female power. And for me, personally, it touches on the issue that women have the right to greater choice in life.” And so she donned the false teeth, unflattering wigs and the long cardigans necessary to play Mary Louise. It’s a sign of just how much she is revered that even the Big Little Lies cast – chock-full of Oscar winners – found it unnerving to star alongside the acting legend. But Meryl has a trick for that. “I’ll forget my lines. I’ll turn in the wrong direction, or do something to shatter any illusions of perfection they might have of me. I want the other actors to think, ‘Maybe she’s not as good as we thought,’ and then they relax and we all feel comfortable.” Of course, Meryl is as good as we all thought. There’s already talk that she will be nominated for yet more awards for her role in Big Little Lies – and very possibly for the upcoming Little Women and The Laundromat as well. But at this stage in her career, it’s not the accolades that drive her. The awards cupboard, both metaphorically and literally, is very much full. So what is it about her characters that keeps her going, striving for more work? “I would say that it’s optimism,” she says. “I enjoy playing women who want to change the word, who are full of hope despite difficult circumstances. And they share the goal of not getting bogged down by the bastards!”

Big Little Lies season two is available on SoHo and Neon.