They are building an area for this 1 concert!
https://abbavoyage.com/thearena
The venue is built around ABBA’s timeless music and never-before-seen concert, so you can have the time of your life in General Admission or have the option of a seat in the auditorium if you prefer.
You can even party in style in your own Dance Booth.
based on this BBC article, it's not a one-off show but rather a recurring "virtual concert" holograph show:
Abba delight fans with new 10-song album and virtual concert.
"The band's new songs will also be played during the band's virtual concert, also titled Abba Voyage, which will open next year in a specially-built arena in east London.
Playing six nights a week, it will feature digital versions of Abba's band members, accompanied by a 10-piece live band performing 22 of their greatest hits. Tickets go on sale on 7 September, starting at £21, with the opening night on 27 May.
The digital Abba show will initially be staged in London, but could tour the world.
The so-called "Abba-tars" were designed by Industrial Light and Magic - the visual effects company founded by Star Wars creator George Lucas."
Abba-tars... yikes.