ABBA stars surprise Mamma Mia! audience

By By Aine Fox, Press Association
Updated April 7 2019 - 11:53am, first published 11:48am
Benny Andersson and Bjorn Ulvaeus have attended Mamma Mia for the show's 20th anniversary.
Benny Andersson and Bjorn Ulvaeus have attended Mamma Mia for the show's 20th anniversary.

Abba's two leading men have made a surprise appearance as hit musical Mamma Mia! celebrated its 20th anniversary.