This bluesy track features a harmonica part, which was improvised on the spot. McCartney told The Daily Telegraph October 10, 2008 that he and his collaborator, producer Martin "Youth" Glover, went into the studio with nothing prepared, and recorded a song a day. He admitted: "I had to make a disclaimer to the engineers I said this could be the most embarrassing moment of my life. It was thrilling, but it could have been a terrible mistake. It could ruin my whole career!" He added: "We were like mad inventors. The process was just to set up a groove and play stuff. Youth would say, 'How about a bit of harmonica?' So I'd play that. 'How about a bit of drums? Guitar? Tin whistle? Throw everything at it, see what sticks.' I think, having written so much over the years, even when I am improvising I have an ability to spot what's working, and just go with that."