Songfacts®:

• The guitar-driven song finds Sheeran singing about a drug experience. It was one of three tracks on x that the English singer worked on with American producer Rick Rubin (the others were "Don't" and "Tenerife Sea.")
• Sheeran explained during the Live From MTV Presents the Ed Sheeran After Show how Rick Rubin helped him focus on the album process. "I think before then the album was good, but it was very much, 'Here's a Pharrell song and it really sounds like a Pharrell song,' and 'Here's an Ed song and it really sounds like an Ed song,' and 'Here's a West Coast hip-hop song that sounds like Benny Blanco' - it was all different songs," he explained. "And I think what the session with Rick did [was] it got me focused on an album process rather than just songs and it tied everything together."
• Sheeran explained during a Spotify track-by-track that the song was written after an experience taking ecstasy in Ibiza, and it's basically about all the feelings that he got from that time. "It was weird," he said, "because I haven't taken it since, it was literally just a one-time thing."
  
  "It was a wedding, and I was having a mojito, and my mate was like, 'Do you want to try it, it tastes really bad if you put it in your mouth but I'll just put it in your drink and it'll be fine'. It was MDMA and I fell in love with a beanbag," Sheeran added. "I literally got home and bought six beanbags! During it all I felt a lot of things: I felt anxiety, I felt love, I felt warm, I felt a bit weird. And afterwards, you spend all day just thinking about what you've been through. So, I've only done it once and I've told my mum and dad about it."
• Sheeran wrote this with Johnny McDaid and Gary Lightbody of Snow Patrol. The singer-songwriter supported Snow Patrol on the North American leg of the band's Fallen Empires Tour in 2012 and he later dropped a Snow Patrol reference in his Fault In Our Stars soundtrack song, "All of the Stars." ("They're playing 'Chasing Cars' and I thought of us.")
  
  The other songwriters were Rudimental. Sheeran performed the song with Rudimental during the English band's set at Glastonbury Festival on June 27, 2014.
• Sheeran re-worked the song for its single release so that it features Rudimental. The accompanying video was directed by Emil Nava and features Ray Liotta. The Goodfellas actor portrays an aging, formerly famous heavy metal frontman in the fictitious group Black Glove, whose rock star lifestyle is finally taking its toll. Nava also did Sheeran's videos for "You Need Me" and "Give Me Love."
• The alternative Rudimental version also appears on the British drum 'n' bass group's album, We the Generation. During an interview with The Sun, Rudimental's DJ Locksmith disclosed regarding the collaboration: "We were working in LA and he rocked up to our studio with The Game and Ellie Goulding."
  
  "We made four tracks and revisited one this year (Bloodstream) to give it a Rudimental spin. We've known Ed for years. I remember when we first saw him getting noticed by everyone, he gave us one of his tracks to remix and he said it was one of the best remixes he'd ever had."