James Blunt has opened up about the making of his Carrie Fisher tribute song Dark Thought.

The You're Beautiful singer - who was a close friend of the late Star Wars actress - revealed it has taken so long to pen the emotional track because he wanted to do it justice.

"It must be about seven years since she died, I'm not entirely sure, but it's taken me all of that time to write a song for her," the 49-year-old singer shared in an interview with New Music Express.

"As a songwriter, the most honest song is normally the easiest to write because it just flows out of you," he explained. "But I've been overthinking this song for so many years because she's just such an incredible human being."

James stayed with Carrie at her LA home when he recorded his debut 2004 album Back to Bedlam.

The When Harry Met Sally star died of a sudden cardiac arrest in December 2016, aged 60.

James wrote Carrie's tribute track, Dark Thought, about visiting the property following her passing.

"What I did with the song is I just described the moment I went back looking for her after her death," the singer explained. "I went back to her house on a whim, drove up to her gate, and put my hand on it just to feel a little bit of her there. And I wrote the song about that moment."

Dark Thought features on James's new album, Who We Used to Be, which was released on 27 October.