Since it was performed by One Direction—a fresh, energetic young boy band—the song strongly projects an image of “sweet and innocent youthful romance.” However, it was actually written by songwriter Savan Kotecha for his own wife.
One morning at a hotel in London, his wife was feeling down and said, “I look so ugly today.” Trying to comfort her, he said, “No, you don’t. You don’t know how beautiful you are.” At that exact moment, a lightbulb went off in his head: “Wait a minute, this would make an amazing song!” He then wrote the rough draft of the song in just two days.