The only member of ABBA to take part in any event during the 50th Anniversary of Waterloo's win at Eurovision was Björn, who was in London for the 25th Anniversary of Mamma Mia!   He went on stage at the end of the show to say a few words.

A few days later, Björn's social media channels released a short video showing Björn at Waterloo Station, in London with ABBA signage behind him, ABBA Voyage advertising on the London Underground, footage of The Piano Moment in London, Warsaw, Berlin and Stockholm, on stage at Mamma Mia! in the evening; the concert in Kungstradgarden in Stockholm and the tribute concert at Cirkus, Stockholm.