Songfacts®:

• Halsey recruited Fifth Harmony singer Lauren Jauregui to help her sing this pro-LGBTQ love song about the moment a relationship turns cold.
  
  She doesn't call me on the phone anymore
  She's never listening, she says it's innocent
  She doesn't let me have control anymore
  I must've crossed a line, I must've lost my mind.
  
  Chatting with the radio show host Zach Sang, Halsey said. "I just love that Lauren and I are two women who have a mainstream pop presence doing a love song for the LGBTQ community. It's unheard of. It's very rare to see it from a female perspective."
• Both Halsey and Lauren Jauregui identify themselves as bisexual women. Jauregui came out in an open letter published in Billboard magazine on November 18, 2016. Halsey said the Fifth Harmony singer was an obvious choice for the duet.
  
  "I was thinking to myself, if I want this song to be believable, it needs to be real, so I'm not going to put a girl on the song to sing who's straight. I'm just not going to do it. So I reached out to Lauren, and she came in and she cut the vocal and it sounds awesome," the singer-songwriter said, adding, "Our voices sound really cool together because we both have really raspy voices. Mine's a little more delicate than hers. Hers is like really powerful and big and raspy, and mine is kind of like light and raspy. But it's really cool."
• The song was co-written and produced by Greg Kurstin, who hasn't collaborated with Halsey before. Kurstin has a impressive resume, having previously worked with superstars like Kelly Clarkson ("What Doesn't Kill You (Stronger)") and Adele ("Hello").
• When the song entered the Hot 100, Jauregui became the second member of Fifth Harmony, past or present, to reach the chart as a soloist, following Camila Cabello.
• The music video is the fifth and final instalment of Halsey's "Hopeless Fountain" saga, which is a collection of short films based on tracks from the Hopeless Fountain Kingdom album. It centers around a modern day "Romeo and Juliet" theme and this clip finds the two star crossed lovers taking their feelings to the boxing ring. Halsey told ABC Radio the video was partly inspired by Christina Aguilera's "sweaty and filthy and really sexy" one for "Dirrty."
  
  Halsey added that she and Lauren Jauregui trained with real boxers and stunt coaches before fighting each other. "'Strangers' is about this relationship where these two people are kinda beating the life out of each other emotionally, it's this like give and take, y'know," she explained. "And it does feel very much like a boxing match. Sometimes one person's winning, sometimes another person's winning, but they're both tired and they don't want to be hurting each other, but they feel like they have to."