"Smile" is a pop song by Lily Allen, written and performed in the key of A major. Released as the lead single from her debut album "Alright, Still" in 2006, the song achieved commercial success, reaching the top of the charts in multiple countries. Lily Allen, a British singer-songwriter, co-wrote the track with Greg Kurstin, who also produced it. The lyrics of "Smile" reflect a triumphant and sassy tone, with Allen singing about getting revenge on an ex-lover. As for trivia, the song samples the piano melody from "Alfie" by Sonny Rollins. The melody of "Smile" is catchy and upbeat, incorporating elements of pop and ska, accompanied by Allen's distinct and cheeky vocal delivery.