G?ran Bror Benny Andersson (born in Stockholm, Sweden on 16 December 1946) is a Swedish musician, composer, a former member of the Swedish musical group ABBA (1972-1982), and co-composer of the musicals Chess, Kristina fr?n Duvem?la, and Mamma Mia!. Currently active with his own band Benny Anderssons Orkester (BAO!), and executive-producing the film version of the musical Mamma Mia!.