Songfacts®:

• Ellie Goulding penned this uplifting track for her best friend, Hannah. It was co-written by hit-makers Max Martin, Savan Kotecha and Ali Payami, the same trio who also came up with the English singer's 50 Shades Of Grey single "Love Me Like You Do."
  
  "I just wanted to show our friendship for what it really is - honest, real, electric," Goulding wrote on her Tumblr when she released the song in October 2015.
• Goulding explained the story behind the song in a letter to her fans:
  
  I realized that I had focused a lot of writing on past relationships and it hit me I had never written about my best friend. The person I met in college over ten years ago. The person who was at my very first gig. The person who has seen me at my lowest and the first person I call in muffled sobs when something bad happens. We've been deliriously happy together, deliriously tired and deliriously sad together. I wanted to show our friendship for what it really is- honest, real, electric.
  
  I think about the times we drink together until neither of us can stand. The laughing at our own ridiculousness and foolishness. Comparing our trials and errors; overthinking our break ups and new loves, remembering everything we've been through to get to this point and being so proud of it. Two girls from Hereford trying our best in the City. We open our hearts up and take risks, but together we are more powerful than ever. We are challenged every day but we see it through and sometimes it feels like we can conquer anything. When I'm with you, I'm standing with an army.
• Ellie Goulding gets on with Max Martin and enjoys working with the Swedish producer. She said in a Genius annotation: "The best thing about making music is that you can work with someone you genuinely love spending time with. So that is good. You get to feel confident and safe with someone, trusting someone, that it is going to be worthwhile."
  
  "We have made some really amazing songs together, but I think 'Army' is probably my favorite. It goes back to my roots, with my guitar. Also I just love writing a good ballad."
• British photographer Conor McDonnell directed the song's black-and-white video. He is best known for shooting Kim Kardashian and Kanye West's wedding, after being spotted by the pair on Instagram.
  
  The clip features scenes of Ellie and Hannah giggling, laughing and dancing as well shots of Goulding singing directly to the camera and performing at music festivals.