Agnetha Faltskog, Bjorn Ulvaeus, Benny Andersson, and Anni-Frid Lyngstad played "Me and I" (from 1980 album Super Trouper) in Stockholm during a private party celebrating the Ulvaeus and Andersson's 50th anniversary as friends.
"It was absolutely amazing. A lot of emotions," said Lyngstad to Expressen. "We've made this journey throughout our history. Benny and Björn in particular. It's been very nostalgic."
The four members have been pictured together occasionally - they gathered earlier this year for the opening of Mamma Mia! The Party - but haven't performed together since 1986.
Despite numerous pleas and offers to reform, the group are adamant about not doing so - even turning down a reported $1 billion payday.
