MIAMI • Camila Cabello has been in love only once. But when it comes to crushes, she is a connoisseur.

The pop singer and songwriter, formerly of girl group Fifth Harmony, has filled pages of notes on her iPhone with ruminations on the sugar rush of embryonic infatuation and its aftermath - words of hunger and grit that her fans turn into Instagram captions and scream back at her in concert.

A pair of suggestive duets in the last two years, I Know What You Did Last Summer with Shawn Mendes and Bad Things with Machine Gun Kelly, have been streamed more than 520 million times, according to Nielsen Music.

Along with her breakout solo smash from last summer, Havana, which has led Billboard's pop radio chart longer than any other song by a solo female artist in the past five years, they have helped turn her into an avatar for girls on the cusp of steeper emotional terrain.

On a December afternoon in a leafy neighbourhood here, Cabello, 20, whose name is pronounced "ca-meela ca-beyo", revisited ground zero of her romantic vicissitudes.

Ten years ago, in the butterfly garden at Pinecrest Elementary School, a young Romeo set a date with her among the Panama roses and gave her her first kiss, unlocking the source code for a bottomless trove of love songs.

"It was this boy that I was obsessed with my whole time in elementary school," she recalled, standing in the garden. "He kissed me on the cheek and I ran away - I still do that when someone wants to kiss me."

Though not yet of legal drinking age, Cabello has come a long way from the schoolyard.

At 15, she was beamed into the homes of millions of Americans as a contestant on the United States version of the reality-singing competition The X Factor.

The show placed her in a five-woman vocal group modelled on One Direction that the viewers at home named Fifth Harmony.

Two albums and six tours followed in a span of five years, during which time Cabello was, if not officially the group's lead, a consensus favourite, with the biggest voice and those disarming eyes.

And then it all went to pieces.

One day, Fifth Harmony were performing at the final stop of the Jingle Ball tour, smiling and hair-flipping. The next, a series of contentious and contradictory statements were released and Cabello found herself on the lonely end of a sharp divide.

That was just over a year ago. In the interim, Cabello has put her hands on the controls of her professional life for the first time.

Her new album, Camila, which arrived last Friday, will test her prospects as a solo proposition. The biggest stars to break away from groups - Michael Jackson, Justin Timberlake, Beyonce - did so from stronger footing, in eras when the music industry was thriving.

Today, Cabello is just one in a cacophony of voices aiming to break through in a harsh, post-streaming environment.

"It's not easy for anybody, regardless of your starting point," said Mr Tom Poleman, the chief programming officer for the radio conglomerate iHeartMedia, which recently booked Cabello solo for its Jingle Ball. "The field is so competitive that you really need the planets to align."

And so for 11 days late last month, in the cocoon of her hometown, Cabello took a break.

She settled into old rhythms at her family home and came to Pinecrest to pick up her younger sister, Sofia, only after wresting herself from a savoured Sex And The City binge. ("In my heart, I'm a Carrie, but sadly I think I act like a Charlotte," she said.)

On a tour of its green, alfresco campus, an old teacher asked whether she would be going on tour soon and she said she was in no rush. "For now," she said, "I just want to be a kid."

Cabello comes from a lineage of strivers. She was born in Havana to a Cuban mother and Mexican father and moved back and forth between Cojimar and Mexico City until the age of six.

One day, her mother, Sinuhe, told her she was going to Disney World and the two spent the next month together riding by bus to an immigration centre at the Mexican border with the US. Sinuhe had been an architect in Cuba, but in Miami, where she and her daughter moved in with a close family friend, she found work in the shoe department at a Marshall's.

Alejandro, Cabello's father, emigrated later and earned money washing cars at the mall. Eventually, the couple saved enough to start their construction company.

"My parents' story helps me to know what's important in life," Cabello said. "A lot of times, you can be here and be on Twitter and you think that the world is the Internet. But I know what it's like in the places my family has come from and the struggles people go through."

Over a feast of Cuban food at one of her family's favourite restaurants in Miami, and in a subsequent interview in New York a week later, she agreed to speak at length about how things fell apart.

She said that her collaboration in late 2015 with Mendes - the first time a Fifth Harmony member released music under her own name - had created tension; that she had asked to help write lyrics for Fifth Harmony songs and was rebuffed; that she initially wanted to stay in the group while working on a solo album, but the other members shut her out instead.

Eventually, she said, she was given an ultimatum.

So she made her choice, basing it on what she said was her conviction that "if anyone wants to explore their individuality, it's not right for people to tell you no".

Since the break-up, she has tried to move on from hard feelings, throwing herself into Camila.

In August last year, the remaining members took a less-than-subtle jab at her with a stunt that opened a high-profile performance at the MTV Video Music Awards. As the camera zoomed in on a platform showing five women in silhouette, one was yanked off the stage as if hit by a truck.

Cabello's eyes welled up as she recalled watching it live. She had been at home in the living room with her mother.

"It definitely hurt my feelings," she said. "I wasn't expecting it, I wasn't prepared for it - especially because, at that point, I'd moved on from it. I was just like, 'What? Why?'"

She gathered herself. "I have to make space for the good stuff to happen in my life," she said. "I don't like holding onto the past, especially when it's stuff that, in my opinion, is just petty."

Her first single as a solo artist was Crying In The Club, an arch, dancehall-flecked power ballad released last spring. Produced by Benny Blanco from an original demo written and recorded by Sia, the track underperformed commercially and was left off the final track list of Camila.

A breakthrough came while she was working with producer Frank Dukes, born Adam Feeney, who has made his name as a prolific but low-key co-conspirator of self-styled stars such as Drake and Lorde. Many potential collaborators had come to the studio armed with sleek, brassy Top 40 munitions in the style of Fifth Harmony hits. But Feeney's approach was more nonchalant.

Over sushi during an early session with Cabello last winter, he played her a deceptively simple instrumental with a prominent salsa piano riff.

It reminded the singer of her birthplace and she wrote the chorus for what became Havana on the spot. "There's not another artist in the world who could have done that song - she just owns it," Feeney said.

Many songs on Camila, which Feeney executive-produced and includes writing by Cabello on every track, are infused with tonal or lyrical references to her Latin heritage.

She said she took inspiration from the Latin music that soundtracked her childhood, as well as more contemporary reggaeton revisionists such as Calle 13 and J. Balvin.

Then she blended those sounds with the auteur pop of artists such as her friends Taylor Swift and Ed Sheeran, hoping to unearth her own original recipe.

"I feel like the best way to come up with something new and different is just to be the you-est you possible," Cabello said. "If you pull from all the different little parts of yourself, nobody can replicate that."

NYTIMES