Songfacts®:

• Sheeran wrote this song at the 2013 Grammy Awards. When the English singer penned the tune, he was feeling somewhat left out as he was at the awards ceremony with his blue-eyed girlfriend and everyone else was doing drugs. He explained during a Spotify track by track that there were, "Lots of people chatting about loads of stuff I didn't really understand, and wasn't interested in, and thinking, 'Shall we just pop off?"'
  
  "We were surrounded by all the musicians I look up to," he added, "neither of us wanted to be there - you just want to be with this one person."
• Speaking during a Live Session on BBC Radio 1 with Zane Lowe, Sheeran explained the song was inspired by a picture in a Thomas Cook package holiday brochure that was on the table showing a blue sea. He thought, "Her (his girlfriend's) eyes kinda look like that sea, what sea is that?" This lead to the song title and some of the lyrics.
• Sheeran debuted the song during a performance at the Teenage Cancer Trust show in March 2014.
• This was one of three songs on x produced by Rick Rubin (the other two were "Don't" and "Bloodstream.") Sheeran told Digital Spy he didn't set out to work with the legendary producer. "It was a weird thing because I wasn't intending for any of that to happen," he said. "Rick Rubin came to a show, we hung out, ended up in the studio and then did a lot of work together. It was literally a very random meeting - I went around for a cup of tea after the show!"