Harry Styles has opened up about his relationship with Taylor Swift in a new song.

Harry and Taylor back in 2012

Harry and Taylor back in 2012

The 21-year-old heartthrob dated the pop star, 25, from October 2012 until January 2013 and has now opened up about their time together in One Direction's new single 'Perfect', which will be released on Friday (16.10.15).

A music source who has listened to the track said: "Harry would never get too specific about Taylor in a song, but the lyrics are definitely going to get fans speculating.

"He doesn't want to dish the dirt but a relationship as intense as theirs has provided lots of inspiration."

The song has been taken from the group's fifth studio album 'Made In The A.M.' - due out next month - and features lyrics about what makes the "perfect" partner.

According to The Sun newspaper, they sing: "If you like when I'm driving with the windows down/If you like going places we can't even pronounce/If you like to do whatever you've been dreaming about/Baby you're perfect."

Meanwhile Taylor previously revealed she wrote five songs in a single week about the curly-haired hunk following their split, including 'Out Of The Woods' from her hit album '1989', which she confessed was about the pressure placed on their relationship.

Speaking in a Grammy Pro video, she said: "It just kind of conjured up all these feelings of anxiety that I had in a relationship where everybody was watching.

"You're constantly just feeling like, 'Are we out of the woods yet? What's the next thing gonna be? What's the next hurdle we're gonna have to jump over? Are we gonna make it to next week?'

"It was interesting to write about a relationship where you're just honestly like, 'This is probably not gonna last, but how long is it gonna last?'"