Katherine Waterston breezes into the breakfast room at Claridge's, late, sleep-tousled and unrepentant about her lie-in. "I think my body just demanded it," she says. "It's been a very hectic year…"
"Hectic" is an understatement. Waterston - delicate, milky-skinned, sporting a boyish crop - at the time of writing - was just about to be propelled to life-changing levels of fame. She can currently be seen starring alongside Eddie Redmayne in the new JK Rowling adaptation, Fantastic Beasts; and Where To Find Them.
One of the most hotly anticipated films of the year, Fantastic Beasts - filmed over six months at Warner Bros Studios in Leavesden, with a budget of £182m - is part of the Harry Potter franchise, albeit in an indirect way (Redmayne plays Newt Scamander, a famous wizard who wrote a textbook that Potter studies at Hogwarts). And like anything associated with the Harry Potter writer, everything from the casting to the costumes will be pored over by fans. There are already forums dedicated to how Waterston holds her wand and the nature of her character Tina's relationship with Redmayne's Scamander. Waterston is still adjusting to the new-found levels of scrutiny: "I spent 15 years as an actor never having to talk about myself and my relationship to my work. It's a private, intimate thing and sharing it is hard."
Not that Waterston, (36), is a Hollywood novice. You might recognise her from Steve Jobs, in which she brought buckets of heart to the role of Chrisann Brennan, the powerless mother of Jobs' daughter. And she was unforgettable as Shasta Fay Hepworth in Paul Thomas Anderson's Inherent Vice, a Pynchon stoner caper, delivering the immortal line to Joaquin Phoenix after a very involved sex scene: "This doesn't mean we're back together." After Fantastic Beasts, she will be seen with Michael Fassbender in Ridley Scott's Alien: Covenant, out next year. The latter is the reason for her newly short hair - the rigours of space travel being what they are, her previously long tresses had to go. "I've come to really like having it short," she says, tugging at strands and looking at me nervously with vulnerable, intelligent eyes.
Yet she remembers once being out of work for a whole year. "The phone still rings, it's just never with good news. Maybe they liked you but they didn't want you for this part. If you're stubborn you can make a meal out of a few crusts of bread," she says. "Sometimes I think I would have quit if I hadn't got Inherent Vice (an American TV show about an LA-based private detective)." Through the tough years, her background helped. "What's comforting about coming from a family of actors is I don't have to explain the struggle. I can just sigh to my sister, 'I had a bad one', and she'll know exactly the profound audition humiliation I am describing."
Her father, Sam Waterston, currently co-starring alongside Jane Fonda, Lily Tomlin and Martin Sheen in Netflix's Grace and Frankie and an Oscar nominee for The Killing Fields, appeared in Woody Allen classics such as Crimes and Misdemeanours in the Eighties, becoming a household name for the TV series Law & Order. Her half-brother, James, and sister, Elisabeth, act, as does her brother-in-law, Louis Cancelmi. "If you have a famous parent you know that being famous doesn't make you superior to anyone else. It just means people smile at you more. Everyone was fawning all over my father but of course the way you look at your parents when you're a teen is often with a… more critical eye."
But now it's Katherine's turn and in Fantastic Beasts she plays a New York witch of Jewish descent called Porpentina (Tina) Goldstein, a repressed character "focused on her work" as a federal wand inspector. The film is set in 1936 but her costume includes men's trousers and an old Victorian blouse because "she's very practical and doesn't give a damn about male attention".
She mentions "waving around a miraculous suitcase", containing fantastic beasts, such as the llama-like mooncalf or the niffler, a kleptomaniac platypus. "They weighted that thing down so much. Eddie was waving it around but embarrassingly I found it considerably harder to lift…" For all the fun special effects, she and Redmayne behaved like committed thespians. "Maybe we're both nerds, but we both felt such a responsibility to the pre-existing audience. Even when we were doing screwball stuff, we were both attacking it in a serious way."
That included working with wand coach Alice Reynolds - who previously helped Redmayne with the physicality of playing Stephen Hawking in The Theory of Everything and again with The Danish Girl. "She had us really engage with what we were trying to use the wands for. Because you can feel like such a jackass with a stick in your hand." They also studied the Harry Potter films. "I know Eddie did steal something outright from Emma Watson - that spell she casts on her parents is so delicate and beautiful…"
It was a "tremendous relief" to Waterston when Rowling tweeted celebrating her casting. "The minute you get cast you worry they've made the most terrible mistake. There's a really awkward stage between being hired and doing the job when it doesn't feel real." The first time she met Rowling was on set, mid-shoot. "I think they held her off from coming because they were worried production would grind to a halt… which it did. Eddie and I were like moths to a flame, we just circled her, staring. We wanted to be near her but then didn't know what to say. And she was kind and sweet enough to pretend something really uncomfortable and strange wasn't happening."
Waterston was actually born in London. "My dad was there shooting a BBC mini-series in which he played [J Robert] Oppenheimer, who invented the atomic bomb. So for years my parents called me "the Oppenheimer baby",' she deadpans. Her mother, Lynn Louisa Woodruff, was a model. "The only way my mother's beauty really affected me was that I always assumed that some day I would look like her. Then late in my teens I
Useful skills for a Potter set. And perhaps equally for Alien: Covenant. How was the chemistry with Michael Fassbender? "It's what they test for when they call you back," she says. "I think it's the same thing as in real life: you like them or you don't, you connect with someone randomly at a party, or you don't." She would love to appear on the London stage, just because "doing theatre is more fun". She is clearly hugely fulfilled by her work - and yet her success threatens to trap her.
I leave her confined at Claridge's doing interviews for the rest of the day, asking pitifully if she can do her next one outside in the sunshine. I wonder when she will next enjoy what she says she likes most about London: "A Sunday roast and a slow day in the pub."
*Fantastic Beasts and Where to Find Them are both at cinemas now.