In a small room in a plush Manhattan hotel, half a dozen journalists are waiting for one of the world's most famous women to take the last empty seat at the table.
Someone mutters darkly about female journalists being reduced to tears. "She doesn't like women in general," adds another. "I heard," a third says, lit up with gossipy glee, "that she and Meryl Streep can't stand each other." And then she - Julia Roberts - enters the room.
She's wearing tight black leather trousers, a sharply tailored tuxedo jacket, thick-rimmed black glasses and ferociously-heeled court shoes. Everything very fierce, rather sexy and all Helmut Lang, apparently. Except, that is, for a big rainbow explosion of a chunky necklace which she made herself.
Famous women so often seem a little smaller in the flesh, as though, unlit by cameras, they've somehow become a quieter imitation of their on-screen selves. Roberts, though, seems to engulf the room with her charisma. The male journalist next to her nods vigorously but fails to actually get words out.
It's a testament to her consummate stardom that she's played more movie stars than any other movie star. There's 1999's Notting Hill, in which she appears as Anna Scott (knowingly described as "the most famous film star in the world") but she also plays a famous actress in 1992's The Player, 2001's America's Sweethearts and 2002's Full Frontal.
Foremost in her arsenal is that smile - so enormous and so absurdly disarming that someone should have worked out a way to harness its power into international conflict resolution. And second, the laugh it launches - that enormous, untrammelled, belly-deep sound; the same guffaw that she makes on the floor of Richard Gere's hotel room in 1990's Pretty Woman. She was, perhaps, the least convincing prostitute in the history of film; however hard she pushed the tough-talkin' shtick, she remained doe-eyed, glowing and somehow unassailably demure. But it didn't matter. The film grossed $464 million worldwide, ensconcing her in the Hollywood A-list.
It wasn't until 2000, though, that Roberts finally won an Academy Award, for Erin Brockovich, with which she also became the first actress to receive a US$20 million cheque for a single film. In it, she played the real-life single mother who, with scant legal training, takes on the Pacific Gas and Electric Company of California and wins. Not so much America's sweetheart, then, as America's premier ball-buster.
But her character in August: Osage County, an adaptation of Tracy Letts's Pulitzer Prize-winning play, makes Brockovich look like a pussycat.
Tolstoy told us that, "All happy families are alike; each unhappy family is unhappy in its own way," but even the great Russian's eyes would have popped at the Weston clan, whose dysfunctions are pyrotechnic in their scale and intensity. Roberts, "sweating and wearing a big butt pad" (her words) is tough and weary and rageful, as Barbara, the oldest of the three sisters in a family. It's a role that might just win her a second Oscar - she's been nominated for best supporting actress.
"I mean I've seen some stuff," she says, "but we're amateurs compared to those Westons!"
Over-eager and overloud laughter greets this, and almost every other of her pronouncements. When she brings things to a close it's with the words, "Haven't we had fun in here?" and she looks indulgently from side to side.
A few minutes later, I get to speak to her on her own. She's sitting opposite a window that's gently breezing into her face, wafting her hair into cover-girl perfection and when I joke about this she roars with laughter. But then adds: "Are you too cold, shall I close it?" and I have to stop her from leaping up to do so. It's a little moment that seems to encapsulate her appeal: on the one hand, her gorgeousness being so egregious that even breezes oblige with their tousle-fanning effects and on the other, her being "real" enough, warm enough, to just get up and shut that darn window.
Roberts's career has spanned a quarter of a century but this is the first time she's worked with Meryl Streep. It seems to have been the deciding factor in taking the part.
"I, like everyone," Roberts says, "have only sat in the dark and watched in awe. To get to watch her up close and to see her be a real-life person, working really hard to be that great, it was a privilege."
In one scene, Roberts's character flies at Streep across the table, shrieking, to wrest a bottle of pills from her hand. "Attacking her physically was ... just ... awful. I felt like a terrible person who would truly go to hell. I might actually go to hell now, I've attacked her so many times."
But the sight of Roberts slamming Streep to the ground is nothing compared to hearing her yell, "Eat the f **king fish, bitch !" repeatedly, with incantatory madness, into the face of America's greatest living actress. "Yeah," she says heavily of the film's already infamous catfish stand-off. "That was the hardest thing for me. That was always the scene where I'd think, 'Oh God, I hope that's not on the week's schedule.' And then finally it appears and you think, 'Oh God, this is it, this is that moment.' It's like," she snaps her fingers, "once you're out of the blocks I couldn't be responsible for anything I did or said."
I ask whether it's more fun to be spitting vitriol than playing the sweeter and more docile characters with which she made her name.
"It's not more fun, really. I mean it was a dream to play this part. But it's ... it's just so painful really. There's no sport to it, it all comes from this agony. The truth of it is so deeply wounded that the fun quickly dissipates."
Do her characters ever stay with her? "Oh I think I leave them behind," she says. "I think we grow weary of one another when the time comes. But, as Denzel Washington once said to me, 'just act'. And that's what it is, it's this great, beautiful job that you have and you pack it away and go home. I feel like I've always kind of prided myself on not being - well maybe it shouldn't be pride, maybe it should be embarrassment - that I'm not really actor-y. It's more like a fly-by-the-seat-of-my-pants instinct, you know? You just throw it against the wall and see what sticks. But this whole film, and that moment in particular, was such that I really had to stay so focused on everything that was going on for Barbara. I had to really figure out the math of what makes Barbara behave this way."
She saw August: Osage County when it was on Broadway and it left her, she says, "pummelled". What's the appeal, then, of making and watching material that eviscerates us like this?
"You know ..." she says, with a sigh, "it's conversation. And it's also the examination of that thing they call 'the human condition', whatever that means to people. 'How do we not be our parents?' Or 'how do we be that of our parents that we like but avoid what we don't like?' So that's why we make these sorts of movies and write these sorts of plays and poems and sonnets and novels, because it makes us all ask those questions and look for better, clearer answers."
Roberts's early life seems as all-American as it comes. She was born 47 years ago in Smyrna, Georgia, to Betty Lou Bredemus, a one-time church secretary and estate agent, and Walter Grady Roberts, a vacuum cleaner salesman. The couple later co-founded an acting school in Atlanta and, after graduating from high school, Roberts followed her brother - the actor, Eric - to New York and signed with a modelling agency.
By 1991, with Mystic Pizza, Steel Magnolias and Pretty Woman to her name, Roberts was a global star and tabloid fascination became even more rabid when she called off her wedding to Kiefer Sutherland - then dogged by a bad boy reputation - days before the ceremony. Roberts, who doesn't do nudity on screen and doesn't swear off screen, has now been married to Daniel Moder, a cameraman whom she met on the set of The Mexican, for 11 years.
"Eleven years, feels like 11 minutes," she says, her voice growing misty. "It's just gone by in the blink of an eye. It's really only all these kids in our house that show that a lot of time has gone by. Otherwise it feels like, you know, me buckling and swooning still."
The couple have three children (Henry, 6, and 9-year-old twins Phinnaeus and Hazel) and it takes a lot for her to leave them to make a film. Now, she only works occasionally, "when it's correct and feels right". "I think I still feel very clear that I owe it to myself as a creative person and a person who's worked their whole life, really, to still have that motion. I think anybody owes it to the people they're attached to, to not ... give up on that."
Nonetheless, she says of her husband and kids, "it's so much more fun when I don't actually have to leave them". Of the months spent shooting in Oklahoma, she adds, "I really thought that there would be ... something electric about being on my own and having this thing to do, and it really never manifested itself. I felt quite heartsick to be separated from my family."
And do the children know that their mother is, well, Julia Roberts?
"It's funny, just as my kids start to figure out that I actually do this for a living, I'm doing less of it for a living. So it becomes a funnily disjointed conversation that we have about it. I mean a little person's point of view is so fascinating and full of good humour. When Mirror Mirror came out, a lot of their peer group saw it," she says, referring to the 2012 fairy-tale adaptation in which she played a campily evil queen opposite Lily Collins' Snow White. "That sparked the most questions. The biggest question being, 'Why can't we see it?' I said, 'Well, I just don't feel good about you going to see a movie where Mommy is slapping sweet Lily's face and pulling her hair!' You know? And they accepted that."
Roberts pulls out her phone and leans in, with a touch of the conspiratorial, to show me a picture of her boys. They look like a Ralph Lauren ad."That's Henry," she says, pointing to the younger of the two, "he's got the matinee idol thing down."
I can't help it, I'm charmed. This, I suppose, is part of what makes someone a megastar - the small gestures which, however calculated, signal that she's just a human and that, just sometimes, she'd really like to be recognised as one too.
August: Osage County is in cinemas now.