Songfacts®:

• The original version of Amy Winehouse and Mark Ronson's hit single was a slowed down R&B version of the tune. Recorded in December 2006, despite initial reservations of it sounding a bit "cheesy," Ronson later realized it was one of the best vocals Winehouse had ever done and handed it over for inclusion on her posthumous album, Lioness: Hidden Treasures. He told NME: "When we started the song it had a kind of '60s Curtis Mayfield arrangement… it's a little more jazz tempo and it's super soulful. I still like the original version more, and when you heard her do it live, it's much closer to that arrangement."
• The song is a cover of a single by the Liverpool group The Zutons, which peaked at #9 in the UK in 2006. It was penned in 20 minutes by their lead singer Dave McCabe about an American friend of his, Valerie Starr, who was having a hard time after getting caught drink driving.
• In 2007 a solo live version recorded by Winehouse for BBC Radio 1's Live Lounge peaked at #37 on the UK singles chart. That version can be heard on the Deluxe version of Back to Black.
• The Zutons' Dave McCabe recounted to NME how Amy Winehouse's cover came to be.
  
  "I met Amy three times in my life," he recalled. "Once at the Mercury Prize, once in the Camden boozer The Hawley Arms, and once when I was hanging around with this Brummie lad called Boo, who was a tit.
  
  He spent all night comparing me to her, saying: 'If you're a 1, she's a 10'. I thought: 'OK, I get it, she's good.' Eventually, I said 'Look Boo, f--k off being a w---er. You've done this for hours and it's pissing me off', and Amy turned round and said: 'Well, you f--k off then!' to me, because he was her mate."
  
  "So, I walked out of the house in the strop, and she followed me and pleaded: 'Please come back. I'm sorry I told you to f--k off," he continued. "I really like that song' ['Valerie']. We went back in and carried on drinking."