Songfacts®:

• "I Miss You" features the voice of Julia Michaels, who has co-written many hits including Justin Bieber's "Sorry" and Selena Gomez's "Good For You," as well as her own chart success "Issues."
• Michaels penned this tune during a solo writing session. She said, "I wrote this one when I was at height of an emotional roller coaster. When I was at the top, this flew out of me."
• Clean Bandit's Grace Chatto spoke to Billboard magazine about the meaning of the track, saying, "It's a simple song, about the unbelievable pain of breaking up with someone you love."
• The song's music video features the Clean Bandit trio and Julia Michaels, all in red ensembles, dancing around the desert outside of Los Angeles. The clip was self-directed. Chatto said: "We got to know each other better in the blazing heat. We experimented with special effects and train tracks."
• Clean Bandit recruited D.R.A.M. for the song's official remix. The band's Jack Patterson said the "Broccoli" rapper's verse added a whole new dimension to the lyrical content.
  
  "We reworked the music and sent it to DRAM's team. When we heard what he sent back, we realized he had brought to life a new perspective on missing someone that's completely different to Julia's," he told Billboard. "[D.R.A.M] talks in a true and honest way that's quite powerful, and we absolutely love his delivery."
• Unusually for Julia Michaels, she wrote this tune on her own rather than with one of her regular writing partners such as Justin Tranter. The only other song Michaels has dropped that she wrote completely by herself was "Don't Wanna Think" from her 2017 Nervous System EP. She recalled to Billboard:
  
  "I wrote it while my ex-boyfriend was in Cabo for his birthday - that's how I started the song and just kind of went from there. I wasn't really expecting it to come out, I was just sort of getting it off my chest. Jack [Patterson of Clean Bandit] played chords and I basically just went in the booth and sang everything as you hear it. A month later, Jack called me and was like 'We're gonna put this out.'"
• Given it was such a personal song, Michaels was apprehensive how audiences would react. But she was reassured as it climbed the charts around the world. "People experience the same emotions," she said. "We've all experienced heartbreak, we've all experienced loved, we've all experienced loss, it's just not the same exact experience, but we've all had those emotions. I always forget that people can find their own perspective in a song like 'I Miss You.'"
• Grace Chatto used to do fire poi as a teenager, which involves swinging around balls of fire on chains. When she volunteered to perform it for this song's video, Chatto thought she'd easily pick the skill up again. "Jack Patterson was like, 'You should practice before we light them,' and I was like, 'No, I'll be fine,'" Chatto recalled to The Sun. "Then I burnt a load of my hair."