Abba stars give first performance together in 30 years

The four members of Abba have appeared together in Sweden to surprise fans with a spontaneous performance. 

The stars gathered on Sunday at a private party to celebrate the 50-year partnership between songwriters Bjorn Ulvaeus and Benny Andersson. 

During the event, Agnetha Faltskog and Anni-Frid Lyngstad performed the Abba song 'The Way Old Friends Do'. 

Ulvaeus and Andersson joined in at the end of the song, marking the band's first public performance in 30 years. 

Footage of the performance is yet to be released, but images of the quartet have appeared on social media. 

Since winning the Eurovision Song Contest in 1974, Abba have sold almost 400 million singles and albums around the world.

The group split up in 1983. 

Their last public performance came three years later, on the Swedish version of TV show This Is Your Life, which was honouring their manager Stig Anderson.