Taylor Swift became ''friends and pals'' with Ed Sheeran as soon as they started working together.

The 'I Knew You Were Trouble' hitmaker and the 'Lego House' singer teamed up to write duet 'Everything Has Changed' for the blonde beauty's forthcoming new album 'Red' in her back garden, and the 22-year-old singer admits the pair had a great working relationship.

She said: ''Both of us are really open, so if he doesn't like a phrasing he'll tell me and if I don't like a chord, I'll tell him.

''It's really cool to have an honest channel where he'll be like, 'No', And I'll be like, 'Yep' and he'll be like, 'No', and I'll go, 'OK I'll change it'.

''He is such an amazing writer and an amazing singer. I don't know, it's just amazing to have his voice on my record.''

Taylor and Ed's close friendship led to them pouring out their feelings for 'Everything Has Changed', which is about how a person's views on the world change when a special someone comes into their life.

She explained: ''We were just talking about the feeling of when you first meet someone and all of a sudden the way that the world looks to you changes.

''Like everything looks different to you because of this one person, because one new person came into your life. It's really cool.''

Taylor admits both she and Ed were desperate to work with each other and just happened to ask their management to arrange a collaboration at exactly the same time.

Speaking to BBC Radio 1, she added: ''I had management reach out and at the same time he was having his management reach out to me because we both wanted to work together at the same time.''