ABBA reunited on stage in London after a virtual concert fans described as «unbelievable».

The iconic Swedish group — Björn Ulvaeus, Agnetha Faltskog, Anni-Frid Lyngstad and Benny Andersson — gathered at the ABBA Arena for the world premiere of their new show Voyage.

It was the first time they had been together in the UK in public in many years.

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The stunning show features digital versions of the stars as they looked in their prime and makes fans feel as if they are seeing them at the height of their fame.

The band members danced and sang together for weeks, and motion capture technology helped create a complete show.

Fans were delighted with the groundbreaking show.

«ABBA Voyage is incredible,» wrote one on Twitter. “It’s amazing, and the creative risks that Benny and Bjorn have taken are breathtaking. It’s very emotional and about aging, frailty and loss as much as it is about the joyous preservation of youth.»

«Incredible show!» said another. “Sound, Light, ABBAtars. You have to see it to appreciate how groundbreaking it really is.”

One said it was the moment they had been waiting for since they were kids, adding that it was an «amazing» and «emotional» show.

«Wow…they look great!» posted by another person.

«I’m crying tears of joy right now, just seeing the 4 of them together is like a little dream come true.»

Critics also gave positive reviews to the show, with The Guardian saying it was «so successful it’s hard not to imagine other artists following suit».

The Telegraph gave it four out of five stars and said it was «a dizzying celebration of the best pop music ever made».

iNews also gave the show four stars and said it was «worth the wait».

Reviewer Kate Solomon said the concert was «sublime» and «flawless».

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ABBA was formed in 1972 and was known for songs such as Waterloo, The Winner Takes It All and Dancing Queen.