Harry Styles' ex-girlfriend features on 'Fine Line'.

The 25-year-old singer/songwriter revealed that the track 'Cherry' on his upcoming second album was inspired by a particularly devastating break-up and he included a voice message from his ex at the end of the song.

Harry has not named the ex but it is believed to be model Camille Rowe, who he dated between 2017 and 2018.

Speaking to Zane Lowe for 'New Music Daily' on Apple Music's Beats 1 Radio, Harry said: ''When we listened back to the album, I asked her to add it in. I think she liked [the song.]

'''Cherry' is about... I wanted it to reflect how I felt then. I was feeling not great. It's all about being not great. Because, you get petty when things don't go the way you want it. There's parts that's so pathetic.''

Cherry isn't the only track which has been inspired by Camille as 'Watermelon Sugar', the second single from the album, also has a link to the stunning model.

Back in 2017, Camille, 33, cited 'Watermelon Sugar' by Richard Brautigan as one of her favourite books, in an Elle interview.

And Harry's close friend Tom Hull - who worked on the new album - previously revealed how Harry's break-up with Camille affected the singer's new music.

He said: ''He went through this breakup that had a big impact on him,'' Hull said. ''I turned up on Day One in the studio, and I had these really nice slippers on. His ex-girlfriend that he was really cut up about, she gave them to me as a present - she bought slippers for my whole family. We're still close friends with her. I thought, 'I like these slippers. Can I wear them - is that weird?'

''So I turn up at Shangri-La the first day and literally within the first half-hour, he looks at me and says, 'Where'd you get those slippers? They're nice'. I had to say, 'Oh, um, your ex-girlfriend got them for me.' He said, 'Whaaaat? How could you wear those?' He had a whole emotional journey about her, this whole relationship. But I kept saying, 'The best way of dealing with it is to put it in these songs you're writing.'''