Dove Cameron may be the most famous American actress that London theatregoers have never heard of.

A star of Disney Channel from the age of 16, she won an Emmy playing the dual lead roles in teen sitcom Liv and Maddie and stars as Maleficent’s daughter in TV movie series The Descendants. She has 25 million Instagram followers and she’s also a pop singer with a natural coloratura soprano range. Now, at 23, and after an off-Broadway run as Cher in the musical adaptation of Clueless, she’ll be making her London debut in The Light in the Piazza at the Royal Festival Hall.

Cameron is tiny, with symmetrical features, but she swears like a trooper and I will come to learn that her on-brand Disney sweetness has been won at the expense of personal tragedy.

She describes The Light in the Piazza — Craig Lucas and Adam Guettel’s 2003 show — as “a true cross-breed of opera and musical theatre”, with a score sung in both English and Italian. It tells the tale of a rich American woman (played in Daniel Evans’s new production by soprano Renée Fleming) who travels to Florence in 1953, where her daughter Clara falls for a young local.

Although Clara is “childlike in lots of ways”, this is Cameron’s first adult role. “It’s nice to be 23 and still be able to play high-school age but in my next roles I’ll be playing 23 or 24,” she says, “and my dream is to do a role like Monster or Black Swan, something ridiculous, horrible, damaging.”
For now, The Light in the Piazza represents the realisation of a long-held ambition. “It’s been my favourite musical score since I was really young, when my family was going on a road trip to the Oregon Shakespeare Festival and we bought the CD for the car and all fell in love with it,” Cameron says. “I’ve wanted to play Clara for so long: I’ve been talking about it in interviews, tweeting about it, I posted a video of myself singing the title song on Instagram. My third tattoo — I have eight now — was this little sun [on her middle finger], which reminds me of the lyric Clara sings, ‘I know what the sunlight can be…’”

Composer Guettel suggested her for the role and producer John Berry concurred. Cameron herself didn’t think twice about uprooting to London. “I’ve spent a lot of time here, doing press for Disney Channel. My boyfriend [Thomas Doherty, who plays Captain Hook’s son Harry Hook in The Descendants] is from Edinburgh, so when he goes to work he comes to London, and we’re inseparable. I love it that [London] feels lived in and you know s***’s gone down here.”

Her latest role promises to be less draining than the all-singing, all-dancing Clueless. During that show’s limited run Cameron had to step out to give her voice a rest — switching between Disney pop, show tunes and her normal operatic range risked damaging it — and to deal with trapped nerves: “I f***ed up my neck and my back. I had two really heavy mic packs and there was a lot of head-whipping, and with the heels I had to wear, the connection here [she points at her neck] got really ruined.”

Cameron was charmingly open about these problems — as she has been about bouts of insecurity and anxiety through-out her life — to her millions of followers, who are “mostly 17 to 24, though I know I have a lot of young fans on Instagram”. Aware of her possible influence, she tries to be as honest as possible, and her undeniable ambition and glossy self-promotion are tempered by introspection and self-analysis. No wonder. “I started in therapy when I was about eight, after my best friend was murdered by her own father.”
Cameron was born Chloe Celeste Hosterman, the younger daughter of parents who ran a jewellery company on tiny Bainbridge Island, near Seattle. Theatre was a central part of community life: she could sing songs from Rent at three, decided she wanted to act at seven, and after her parents divorced, persuaded her mother to move to LA when she was 14 because film and TV offered more roles for tweens than theatre. A year later her father killed himself. Dove — her father’s nickname for her — and her family suspect he was secretly gay.

Thus began an extraordinary double life. On the outside she looked like a “very optimistic, bubbly person” but inside “I was a mess, miserable, crying every night, not eating, so anorexic because all I wanted was approval. I was just so sad, truly sad.” At 15, she got into a “horrendous relationship”, her first, with a man she describes as suffocating and controlling. And then she became very famous very quickly.

A Disney scout had spotted her singing in a choir and when she was 16 put her in the show that became Liv and Maddie. The pilot was watched by 5.8 million, and spin-off singles propelled her into the Billboard Kid Digital Songs Chart. In 2015 the first Descendants movie was seen by 6.6 million people, and spawned Billboard 100 hits and two sequels. Cameron’s social media following grew and grew. It sounds like a recipe for child-star burnout, but she credits work and Disney’s paternalism with getting her through the nights when she’d lie awake “inconsolable and crying, guttural heaving for hours and hours”.

From 2013 she dated Liv and Maddie co-star Ryan McCarten, and formed pop duo The Girl and the Dreamcatcher with him, but they split shortly after getting engaged in 2016. She and Doherty were friends on set before they became romantically involved in December that year, but their relationship coincided with a breakthrough in her therapy. The couple have just bought a house in LA and she calls him her soulmate. “He’s the rest of my life, for sure. I know I sound like a 23-year-old in love, I know I sound like an idiot, but with my experience of life and death and romance and coming and going, it’s just one of those cosmic things you can’t really say no to.”

They got matching tattoos within two weeks of getting together: he has a version of the sun symbol inspired by The Light in the Piazza on his knee. As she says, maybe it was meant to be.