Taylor Swift has opened up about why not everyone who comes into her life on a romantic level ends up inspiring her music.

The 28-year-old had a conversation with model Pattie Boyd – who was a muse for both Eric Clapton and George Harrison– where she discussed the "mystical" moments in songwriting that she can't quite put her finger on.

Pointing out that some relationships have hmore of an impact on her imagination than others, Taylor admitted: “I don’t know what it is that makes some people really creatively inspiring.

She continued to Harper's Bazaar: "There have been people I’ve spent a lot of time with who I just couldn’t write about ... It’s just that some people come into your life and they have this effect on you."

As for the process of writingitself, she said: “There are definitely moments when it’s like this cloud of an idea comes and just lands in front of your face, and you reach up and grab it.

"A lot of songwriting is things you learn, structure, and cultivating that skill, and knowing how to craft a song. But there are mystical, magical moments, inexplicable moments when an idea that is fully formed just pops into your head."

While she admitted that things can get “complicated” further down the production line, Taylor revealed that the lyrical part is still just as “uncomplicated" as it was when she was "12 years old"writing songs in her bedroom.