Abba's four members made their first public appearances in 14 years at the London premiere of Abba Voyage.
For the opening night concert, Agnetha, Frida and Benny reunited. The concert features digital versions.
Frida watched the show while Benny clapped to Dancing Queen. Frida was a big grin on her face.
The curtain call was made at the end to a roaring applause.
Agnetha Faltskog, singer, said that Abba "has never left us", in her statement to the BBC red carpet.
"It wasn't difficult to reunite because the music is part and parcel of us.
Anni-Frid Lyngstad added, "I had a dream of this for many years." "We love our music and we love singing."
A host of music stars attended the launch night, including Kylie Minogue and Sophie Ellis-Bextor as well as Jarvis Cocker, Jarvis Cocker, Keira Knightley, and Jarvis Cocker.
The audience included the Swedish King Carl XVI Gustaf, and Silvia, his wife. This meant that there was a Dancing Queen real in attendance.
This concert was in the making since 2016. It features groundbreaking new technology that recreates Abba's 1970s glory, playing hits such as SOS, Voulez-Vous, and Lay All Your Heart On Me.
The band performed for five weeks in motion capture suits, using 160 cameras to scan their facial expressions and body movements.
These became the starting points for hundreds upon hundreds of animators, visual effects artists and designers to create avatars of the band during their peak.
The characters, affectionately called "Abbatars", are not 3D Holograms. This is something everyone involved in production insists.
Producer Baillie Walsh said last year that he didn't believe any hologram shows had been successful to Dazed magazine. "They're not that interesting after five minutes."
Instead, characters are displayed on a huge 65 million pixel screen with lights and other effects blurring any distinction between digital elements and the "real" world in the arena.