Songfacts®:

• Many of the songs on Sam Smith's In the Lonely Hour album, including this one, were inspired by his unrequited love for one person. He explained to Interview magazine. "My album focuses on unrequited love quite a lot because I don't think it's spoken about enough in music. I've been through it myself and I found it hard to find songs that were about that, so I've definitely tried to make that a part of my album."
  
  Smith added: "When I was going through that, instead of searching for songs by other artists to relate to I could listen to my own music. I'd do a song in the studio and it would explain everything I'm going through so perfectly that when I went home and I felt down I could listen to that to make me feel better. It's a documentation of my life. I think it's just important to put it out there."
• The Luke Monaghan-directed video follows a love triangle involving Smith and two close friends set in Paris. The female is played by model Daisy Lowe, daughter of Bush lead singer Gavin Rossdale. The clip marked the first time that Smith publicly addressed his sexuality.
• Smith told 4Music: "'Leave Your Lover' is about someone I fell in love with last year. I tried to make this track sound pretty because the message of the song is pretty sad."
• Smith felt closure after telling his unrequited love that the In the Lonely album was based on him. "I told him before the album came out and it gave me a lot of closure actually," the singer revealed to ITN News. "It made the whole; it just put a bookend at the end of the record. It was amazing. I'm so happy I did it."
• Sam Smith wrote this song with Simon Aldred, who is the frontman of the rock band Cherry Ghost. Smith told Digital Spy the story of the song. "We were in his living room having a cup of tea and I was completely entranced by the chords," he said.
  
  "I immediately came up with that lyric, 'Leave your lover, leave him for me'. I remember feeling so proud that I got the word 'him' in. We just put that down as a demo and it took about an hour to write - then we went and got a bagel together!"