This is what we found on Wikipedia regarding the ABBA Voyage:

ABBA Voyage is a virtual concert residency by the Swedish pop group ABBA. The concerts feature virtual avatars (dubbed 'ABBAtars'), depicting the group as they appeared in 1979, and use vocals re-recorded by the group in a Swedish studio specifically for this show, accompanied by a live instrumental band on stage. The concerts are held in ABBA Arena, a purpose-built venue near the Queen Elizabeth Olympic Park in London.

The digital versions of ABBA have been created with motion capture and performance techniques with the four band members and the visual effects company Industrial Light & Magic, in what is the company’s first foray into music.

The ABBA Voyage concert is produced by Svana Gisla and Ludvig Andersson, director Baillie Walsh, co-executive producer Johan Renck and choreographer Wayne McGregor.

According to multiple media reports, the project is one of the most expensive live music experiences in history, with a budget of $175 million. The show was nominated for two categories at the 21st Visual Effects Society Awards, losing Outstanding Virtual Cinematography in a CG Project to the science-fiction film Avatar: The Way of Water, but winning Outstanding Visual Effects in a Special Venue Project.