**Grease** was not co-produced by Bjorn but Allan Carr, who also produced musicals like "Grease 2" and "Xanadu". Bjorn is actually a member of the Swedish pop band ABBA, famous for songs like "Dancing Queen" and also the movie "Mamma Mia!".
The Melodic Journey of Björn Ulvaeus: How Well Do You Know the Swedish Musical Legend?