Bjorn Ulvaeus and Benny Andersson, the composers of Broadway's Chess and Mamma Mia!, made a rare group appearance with their former ABBA co-stars Anni-Frid (Frida) Lyngstad and Agnetha Faltskog Jan. 20 in Stockholm.
The reunion, according to Billboard.com, celebrated the opening of the ABBA-inspired restaurant, Mamma Mia! The Party. The group last performed together in 1986.
"We are here to party," Ulvaeus said at the event.
Watch video of the reunion below: