Olivia Rodrigo sings about heartbreak but she's already chosen her wedding song

Into every life a little rain must fall - but nothing could prepare Olivia Rodrigo for Hampstead Heath in June.

We're supposed to be filming an interview in the park, but the heavens have burst. It's not just raining cats and dogs, but otters, dolphins and multiple other water-dwelling mammals.

As the monsoon monsoons, our lights and cameras are hastily scooped up and moved into the beautiful Victorian kitchen of nearby Kenwood House.

It's a scramble, but everything's in place (just) when Rodrigo arrives - not a hair out of place, after a short but windy walk from her car to the set.

Although it's an early start, the 23-year-old has already been working. On the journey over, she made final tweaks to a new song called Maggots For Brains, just 10 days before its release.

"I love that song musically, and there's a lot going on - a lot of harmonies - and literally in the car, I was like, turn that backing vocal up just one decibel," she says.

"I was getting kind of weird about it. Nobody else will notice."

We've chosen Hampstead Heath because it's one of Rodrigo's favourite places in London – an open space where she can generally walk around without being bothered.

"It's the best place to hang out," she says. "Nobody's ever been weird, I guess because it's so spread out?

"One time, I even saw someone propose. I was sitting on a bench, and I looked over, and there was a huge commotion, and all the couple's friends were there. It was so sweet."

It's a scenario she's dreamt about. Ideally, Rodrigo would also receive an outdoor proposal in New York's Central Park.

"I'd love it if someone paid for a placard on one of the benches that said, 'Will you marry me?'," she laughs. "Then you'd sit down and you're like, 'Oh my God!'

"So spread the word... Hopefully my future husband will see this."

If you are out there, prospective Mr Rodrigo, you should also know your wedding song has been pre-selected.

"It's going to be I Melt with You by Modern English," Rodrigo says, humming the intro.

"Imagine kissing and then walking back down the aisle to that? I love that song."

It's reassuring to hear her faith in love remains intact.

Anyone who's listened to Rodrigo's first two albums, 2021's Sour and 2023's Guts, knows the singer has endured a few calamitous heartbreaks, approaching them with a mix of anguish, confusion and feminine rage.

She didn't write her first true love song until 2024: So American – a punchy new wave cut, about falling head over heels for English actor Louis Partridge.

Before long, her Instagram page was filled with photos from Wimbledon and double-decker busses.

Headlining Glastonbury last summer, with Partridge at the side of the stage, she changed the lyrics from "I think I'm in love" to "'Cause I'm in love".

So when she sat down to write her third album, she thought it would be pretty straightforward.

"I really wanted to capture romantic joy and pleasure for the first time, because my last two albums were very heartbroken and really angsty," she says.

But one look at the title – You Seem Pretty Sad for a Girl So in Love – suggests paradise wasn't what it seemed.

"It's a love story that falls apart," she confirms.

"A time capsule of a relationship in a few years of my life."

It opens in a London pub, where Rodrigo is besotted by a boy who "looks like an angel on the walls of Versailles". He's so pretty she's paranoid she made him up. If he kisses her, she might drop dead.

"When you're really deeply in love, it feels like a song is so futile," she says. "It's really hard to capture in a way that feels palpable to others."

As the album progresses, however, doubts and anxieties creep in.

Everything hinges around track seven, Purple. The lyrics are happy, but the chords never resolve to the harmonic centre, creating a feeling of instability.

"Initially, it was a love song, and it was very sweet and saccharine," says Rodrigo. "And a few months after we wrote it, we revisited it and put new chords underneath it and tweaked some of the lyrics.

"So, yeah, it's definitely the part of the album where things start to sour and unravel."

A similar fate befell What's Wrong With Me – a duet with her musical hero, The Cure's Robert Smith.

It was originally written about missing someone so intensely she felt listless and depressed. Rodrigo revised the lyrics post break-up, after realising the relationship itself was the source of her sadness.

"I can't eat, I can't sleep / I think you're what's wrong with me."

She and Smith debuted the song last weekend at Spain's Primavera Festival. Backstage, the British star was full of praise for his protégé.

"She is genuinely fantastic, as a singer, as a songwriter, as a performer," he told BBC 6 Music. "I'm slightly in awe of how easy she finds it all."

It was their second appearance together, after duetting at Glastonbury last summer.

Universally acclaimed as the set of the weekend, the performance confirmed Rodrigo as a generational talent, equally at ease with lighters-aloft balladry, and rabble-rousing pop-punk antics.

Backstage, though, she was a bag of nerves.

"I remember having like a near anxiety attack in the bathroom, like, 'How am I going to do this? I don't know if I'm ready.'

"But something overcame me the second I stepped on stage and started singing. I felt, like, totally calm and so in my element.

"I'm not very spiritual or religious, but it's moments like that where I feel music is just so magical that you just can't really describe it."

It was also a performance powered by an impressive amount of dessert.

"I stayed at this [hotel] that had the best sticky toffee pudding, and I was like, 'You know what? I gotta do it'," she laughs.

Three bowlfuls were consumed before she took to the stage.

"If the toffee's really hot and the ice cream melts on top, it's really good."

Pudding isn't her only British culinary weakness.

"My favourite thing is dipping soldiers into an egg," she says. "I got really obsessed with it. My friends even bought me different egg cups from all over the world."

That's the charm of Olivia Rodrigo. She may have grown up in showbusiness, working on multiple Disney shows before launching her music career, but she's neither cosseted nor precious.

One of the reasons she loves the UK is that it gives her perspective.

"I feel so normal here, very adult. I can walk to the pub and meet friends. It's a city where spontaneity is really encouraged. People are very social here, in a way that they're not in Southern California."

And, for someone with 40 million Instagram followers, she seems resolutely unbothered by other people's opinions of how she should behave.

She's been outspoken about the curtailing of reproductive rights in the US, and the humanitarian crisis in Gaza.