Ryan Adams and Taylor Swift have recorded a duet.

The 42-year-old musician previously covered the 'Shake It Off' singer's entire '1989' album and explained he did so because he was fascinated by her writing process, and he also found the lyrics struck a chord when he was going through a divorce from Mandy Moore.

He said: ''Taylor is my friend - she and I had recorded a song together that no one's ever heard - and I wanted to know how far she went from acoustic to her finished songs.

''I wanted to break it back down to the acoustic. It took five or six days and never stopped being fun.

''Plus it was kind of cathartic because her words were actually matching s**t I was going through.''

Ryan channelled his own heartbreak into his most recent album 'Prisoner' and though there are still a lot of songs he didn't put on the record, he took a break from recording that to focus on his '1989' project because he was ''tired'' of his own work.

He told Vanity Fair magazine: ''I was in New York at Electric Lady Studios and being back and in that zone opened me up.

''I wrote so many songs for 'Prisoner' - there are still 22 that people don't know yet and are much more f***ed up - but I was getting tired of playing my own stuff.''

Ryan previously praised Taylor's songwriting abilities and claimed covering her tracks made him step up his own work.

He said: ''[It was like] being in Ghostbusters or something, and then all of a sudden I have to go do Shakespeare...

''Those songs are popular for a reason. She's a popular artist for a reason.''