In the space of three years, Griff has gone from recording songs in her bedroom to touring the world with Coldplay and Taylor Swift.

The speed of her ascent has been dizzying. So much so that she called her debut album Vertigo.

But Griff's success hasn't been a surprise to everyone - not to the Brit Awards, who named her a rising star in 2021, nor to the BBC, which put her on its new talent hotlist in the same year.

Born Sarah Griffiths, she signed to Warner Records in 2019, and her emotionally vulnerable pop songs went viral during the pandemic thanks to what she called her "lockdown content hustle".

She emerged with a hit single, Black Hole, and a rush of support slots for artists like Ed Sheeran and Dua Lipa.

"The challenge is to try and win over 80,000 people who are not there to see you," she says.

"I learned that people just want to have fun and dance. So I would cut my slow songs, make it a fun time, not take it too seriously."

For a singer who dreads the stage ("there's something about the scrutiny and the judgement that still terrifies me"), the experience was life-changing.

"I think I've learned that nerves never go away," she says. "Like, I get sick to the stomach every single time.

“But it’s a unique high, having people sing [your words] back to you.

"Every now and again, without asking, a whole stadium would start putting their lights up. And that's when you really feel like, oh my God, I've really got this audience."

All those tour dates might have delayed her debut album, but it was worth it. When Vertigo was released last week, the fans who'd discovered her in stadiums around the world were ready. It entered the UK chart at number three.

When we last spoke in 2020, Griff told me she'd never had her heart broken.

Songs that appeared to be about relationships were often about friends she'd lost touch with or the foster children who moved through her parents' house in Hertfordshire.

Vertigo, on the other hand, appears to be a straightforward break-up record.

"It might have happened, yes," she confirms. "But I think that's naturally what you experience in your early 20s."

How did the real thing compare to the scenarios she imagined in her teenage songs?

"It's just tougher, maybe, than you think.

"Being let down or feeling rejection is harder to articulate than you can imagine."

On the record, however, she has a talent for finding the fault-lines in relationships and exposing them with unsparing clarity.

“You’re scared of love / Well, aren’t we all?” she sings on the title track.

The album’s most emotionally naked song is Astronaut, in which Griff reluctantly (and sarcastically) sets a lover free: "You said that you needed space? Go on then, astronaut."

Originally a darker, synth-heavy ballad, it changed completely after Coldplay's Chris Martin asked to hear some of Griff’s work-in-progress.

"Chris, very kindly, sat down for an evening and listened to a bunch of songs with me – and he picked up Astronaut as one that I just needed to slow down and strip back. So I asked if he wouldn't mind helping me with that."

They quickly booked a studio and recorded the song live, without a click track, allowing them to linger on the song's most emotional passages.

"And now all you hear is Chris on piano and my vocal, essentially. It’s just one take."

That wasn’t his only contribution. Griff says touring stadiums with bands like Coldplay "subconsciously" affected her songwriting.

"I don't think I went in being like, 'Right, I now need to write like A Sky Full Of Stars'," she laughs - but the big, singalong choruses of songs like Miss Me Too and Tears For Fun are deliberately designed to be "euphoric and congregational".

Congregational is a key word.

Griff grew up as a member of Hillsong, the non-denominational Christian megachurch that began in Australia in 1983 and has reportedly counted Justin Bieber, Lana Del Rey, Selena Gomez, Drake and the Kardashian sisters among its members.

The church's services are more like rock concerts than the traditional diet of hymns and sermons – and they taught Griff about the power of music.

Hillsong also gave her a sense of belonging that she didn't feel at school - which she once described as "probably 97% white".

For a long time, she rejected her heritage - her Chinese mother came to the UK as a refugee, while her father was the son of Windrush-generation parents. But, even so, she felt a career in pop music was off-limits.

"I didn't think that was my space to take up. I thought I had to be an R&B or a soul artist, because pop doesn't feel like it welcomes anyone that looks like me."

That's starting to change. Griff shares this week's top 10 with British-Liberian singer Cat Burns and references Raye's success as a positive sign - but says there’s still a long way to go.

"I still think the UK is yet to see an artist of colour that really, really breaks internationally," she says.

"There are moments, and there's small fires, but for some reason we fail to fan the flames and sustain long touring careers.

"It's up to everyone to figure out why and work out how to support it."

She's encouraged by the acclaim being heaped on Charli XCX – who is of British-Indian heritage and, like Griff, produces her own material.

And she talks glowingly of the remix of Charli's song Girl, So Confusing, where Charli and Lorde discuss how the music industry complicated their friendship.

"That song was so impactful to so many girls because the competition is real," Griff says.

"You’re expected to be picture perfect and support everyone - but we're in an industry that really does, like, pit you against each other, whether someone's telling you about [sales] numbers or comparing you with someone else or bitching about you. It can be so toxic.

"And I think that's why that song was so unique, because the girl dynamic can be so complex, functioning within a world of misogyny."

Luckily, she has the right people in her corner. Not just megastars like Chris Martin and Dua Lipa, but fellow up-and-comers Holly Humberstone and Maisie Peters.

"We're always checking in on each other. 'Are you still alive?', 'Yes, I'm alive!'," she laughs.

More importantly, at least as far as her profile goes, Griff has the support of Taylor Swift.

After promoting her music on social media, Swift invited Griff to play with her at Wembley Stadium last month.

"This girl, she is so creative on every single level," the US superstar told the audience, like a proud mum.

Griff says the atmosphere backstage was "surprisingly calm", given the scale of the show.

"What was really nice about it is that every single person on that tour is aware that they're part of history. There's such a gratitude to being a part of it. And I think that's really a beautiful atmosphere to be around."

So, has she ever considered the possibility of headlining a stadium show of her own?

"It’s weird, my goalpost of success keeps shifting the longer I'm in this," she says.

"My ultimate goal is just to write songs that outlive me - but if that involves performing in stadiums, then that's super inspiring."