So, is Harry Styles' Special One Kendall Jenner or Taylor Swift?
Online speculation has swirled after the One Direction singer revealed in a Rolling Stones magazine interview that his upcoming album is almost entirely about a former lover.
"She's a huge part of the album," the 23-year-old said, without letting on who the inspirational one is.
"Sometimes, you want to tip the hat, and sometimes, you just want to give them the whole cap... and hope they know it's just for them," he added.
Styles - who debuted his single, the Prince-riffing Sign Of The Times, earlier this month - dated Jenner, the half-sister of reality television star Kim Kardashian, in 2014.
Jenner, 21, drew flak recently for her involvement in a Pepsi advertisement which took a simplistic view of fighting global injustices.
Styles was also in a relationship with Swift, 27, for a few months in 2012. Swift reportedly detailed their time together in two songs - Out Of The Woods and Style - in her hit album 1989 that was released in 2014.
Asked for his take on those rumours, he said: "I mean, I don't know if they're about me or not. I'm lucky if everything (we went through) helped create those songs.
"That's what hits your heart. That's the stuff that's hardest to say and it's the stuff I talk least about," he added.
He is also diplomatic when it comes to another topic - criticism of One Direction's music from Zayn Malik, who quit the British boyband in 2015.
Malik, who has forged a successful solo career with a more R&B approach, has said that the boyband's songs are "not music that I would listen to".
Styles said: "I think it's a shame he felt that way, but I never wish anything but luck to anyone doing what they love.
"If you're not enjoying something and need to do something else, you absolutely should do that. I'm glad he's doing what he likes and good luck to him."
Styles also defended the musical tastes of young girls, many of whom are slavish fans of boybands. "Who's to say that young girls who like popular music have worse musical tastes than a 30-year-old hipster guy?" he noted. "That's not up to you to say. Music is something that's always changing. There's no goal posts.
"Young girls like The Beatles. You gonna tell me they're not serious? How can you say young girls don't get it?"
And will One Direction - which Styles had suggested to his bandmates in 2014 for everyone to take a hiatus - make music again?
"I love the band and would never rule out anything in the future," said Styles, whose self-titled album will be released on May 12.
"The band changed my life, gave me everything."