Kate Winslet isn't known for making diva demands but the Titanic star kept the costume and props departments on their toes on the set of her new action film Divergent.
The Oscar-winner was five months pregnant with her son Bear Blaze when she shot the blockbuster, meaning every effort had to be made to disguise her growing baby bump.
"Behind the clipboard, behind the iPad, oh, anything to hide it," the mum-of-three recalls with a mock roll of the eyes.
"It was great actually. Bear was there, hiding under my coat the whole time. And I suppose it won't be that long before he can see it.
"Mia and Joe (Winslet's older children, aged 13 and 10) can't see most of the films that I've been in 'til now, and they won't for a long time but little Bear will probably be able to see Divergent in 10 or 11 years' time."
It's been four months since Winslet - who wed third husband Ned Rocknroll, the nephew of Virgin Group founder Richard Branson, in December 2012 - gave birth to Bear but the 38-year-old isn't displaying any signs of new baby exhaustion when we meet.
Dressed in a chic jacket and pencil skirt, her skin glowing and blonde hair pinned back in loose waves, she exudes calm, while those around her rush to keep a hectic set of interviews on track.
What's her secret?
"Because I've done it before, and know exactly what to expect, particularly from this phase when they're so small, I am just really, really relaxed," she says.
"It's just lovely. When you're going through it for the first time, and I was only 25 when I had Mia, you are more anxious - 'Why are they upset, what do they need?' There are just lots more questions.
"But now it's like 'They're only crying because they're tired. It's fine, they're hungry, it's fine!' You just kind of know a little bit more. It's more instinctive."
And the actress has "no shortage of little helpers" in the form of Mia (her daughter from her first marriage to Jim Threapleton) and Joe (her son with second husband Sam Mendes).
In Divergent, based on the first novel from Veronica Roth's bestselling trilogy, Winslet plays a villainous leader in a dystopian Chicago, where youngsters are divided into factions based on their personality traits.
"I've never really played an evil person before now," the actress says.
"It's been fascinating for me playing someone who is quite blatantly cunning and manipulative."
She describes her character, Jeanine Matthews, as a "female Hitler".
The film's themes, of fitting in and finding your identity, were "probably the biggest pull" for Winslet, and brought back memories of her own teenage years, she says - although arguably hers wasn't an average adolescence, with a stint on BBC youth series Dark Season and a big- screen debut in the 1994 film Heavenly Creatures both under her belt before she'd even turned 18.
"It really resonated with me, and I think that's what's going to resonate with a lot of people of that age who do go and see this film, because it's such a confusing time," she says.
"You have questions about absolutely everything: who you are, what you want to be, what's going to happen in the world; what if, and when.
"Just this notion that you have an opportunity to choose to stay with your family, or leave and be in the faction of your choosing, and being true to yourself, the fact that these individuals are forced to stop and really think about who they are, that's an important moment I think in anyone's life."
Does she worry about her own children becoming young adults in such a challenging world?
"I think it is tough for teenagers, and it's definitely tougher for parents of teenagers, simply because we have to protect them from a lot more, I think, than perhaps when I was growing up," she muses.
"So far, I'm not worried for them, they're pretty feisty little people. But I'm sure that will all change."
Winslet is fairly feisty in her own right, and was keen to perform her own stunts in Divergent, until nervous bosses insisted she use a double.
She's looking forward to delving into her dark side again for the film's sequel - and being a bit more "kick-ass" this time.
"Even though I loved everything about the experience first time around, when I'd had the baby we had to go back and do four days of reshoots, and the baby was only about seven weeks old and my brain actually felt much more awake.
"Because when you're pregnant, so many more brain cells go to the baby that you sort of walk around in this slight fug. And I really did feel as though I was sort of awake again," she says.