"Watermelon Sugar" is a song by English singer Harry Styles from his second studio album Fine Line (2019), included as the album's second track. Styles wrote the song with Mitch Rowland and the song's producers, Tyler Johnson and Kid Harpoon. They were inspired by the American novel In Watermelon Sugar (1968) by Richard Brautigan. "Watermelon Sugar" is a horn and guitar-driven funk-pop, rock, indie pop song.