Björn Ulvaeus, Agnetha Fältskog, Anni-Frid Lyngstad and Benny Andersson reunited for the opening night of the concert, which features digital versions of the band.
The concert has been in the works since 2016 and features ground-breaking new technology that recreates the sight of ABBA in their 1970s prime, playing their hit tunes.
To create the spectacle, Björn, Agnetha, Frida and Benny performed in motion capture suits for five weeks, with 160 cameras scanning their body movements and facial expressions – and they became reference points to create avatars of the band in their heyday. If you must know, one thousand visual effects artists created the show and it took one billion computing hours to animate the avatars.
Affectionately known as "ABBA-tars", the characters are not 3D holograms – as everyone involved in the production is at pains to point out.
"I don't think any hologram shows have been successful", producer Baillie Walsh told Dazed magazine last year. "After five minutes, I don't think they're that interesting".
Instead, the characters appear on a massive, 65-million-pixel screen, with lights and other effects blurring the boundaries between the digital elements and the "real world" in the arena.
"We want to pull on the emotions", producer Svana Gisla told the BBC. "So, if you come out of here and feel like you've seen a visual spectacle, we will have failed. If you come out of here and you've laughed and you've cried and you can't wait to go back, that's what we want".
Amazingly, they've pulled it off. The images might be 2D, but impressive lighting effects – 500 lights in the purpose-built arena – and back projections provide a crucial depth of field – creating the illusion that the band are really in the room with you.
Although the band members were in their 70s when the motion capture footage was filmed, the Royal Ballet's resident choreographer Wayne McGregor helped them recreate the movement of their younger selves.
Agnetha and Frida's home-spun dance routines, which could charitably be described as "extravagant walking", are both instantly recognizable and achingly nostalgic.
The music is enhanced by a precision-drilled, 10-piece live band, who race through an eclectic set of ABBA songs that mixes classics like “Mamma Mia” and “Thank You For The Music” with unexpected deep cuts such as “Eagle” and the tender “When All Is Said And Done”. The two new songs they released last year, “Don't Shut Me Down” and “I Still Have Faith In You”, slot into the setlist seamlessly; while the footage of the band winning the Eurovision Song Contest in 1974 elicits an audible "aaaahh" from the audience during “Waterloo”.
And of course, the absolute highlight was that the foursome came on stage at the end. The quartet didn't speak during their brief appearance on stage – but, by then, the concert had said everything they needed to say.
The show takes place in the 3,000-seater Olympic Park at Pudding Mill Lane, London E15 2PJ and is currently due to run until December 2022. Then, in true Swedish style, the venue can be collapsed into a flat-pack and taken on the road.
It's the perfect solution for a band who swore never to tour again after they dissolved in 1982 – even turning down a $1 billion offer to play 100 shows at the turn of the Millennium. But the new technology, pioneered by Star Wars VFX company Industrial Light & Magic, tempted them back into the live arena.
