Mamma Mia! is a jukebox musical with a book by British playwright Catherine Johnson, based on the songs of ABBA, composed by Benny Andersson and Björn Ulvaeus, former members of the band. It was an early example of the jukebox musical genre and helped to popularize the form. Although the title of the musical is taken from the group’s 1975 chart-topper Mamma Mia, the plot is fictional, not biographical.