Bjrn Ulvaeus was a part of a phenomenal Swedish pop group, formed in Stockholm in 1972, as well as co-producer on the film "Mamma Mia!" with Benny Anderson.
ABBA (] ) were a Swedish pop group, formed in Stockholm in 1972 by members Agnetha Fltskog, Bjrn Ulvaeus, Benny Andersson, and Anni-Frid Lyngstad. 
Bjrn Kristian Ulvaeus (] ) (born 25 April 1945; credited as Bjrn Ulvus) is a Swedish songwriter, producer, a former member of the Swedish musical group ABBA (19721982), and co-composer of the musicals "Chess", "Kristina frn Duvemla", and "Mamma Mia! 
 He co-produced the film "Mamma Mia!" 
 with fellow ABBA member and close friend Benny Andersson. 
