AceShowbiz - ABBA star Bjorn Ulvaeus has opened up on the creation of the group's avatars for their forthcoming hologram tour.

The "Dancing Queen" hitmakers first announced their reunion back in 2018, promising two new songs - their first in four decades - along with plans to hit the road with the holograms.

While neither project has surfaced as yet, the band is still working behind the scenes amid the pandemic to ensure the tour goes ahead.

Discussing the process of creating the avatars, Ulvaeus told The Times newspaper the bandmembers were "photographed from all possible angles" and made to "grimace in front of cameras."

"They painted dots on our faces, they measured our heads," he recalled.

And the "Mamma Mia" star also discussed how Agnetha Faltskog and Anni-Frid Lyngstad's vocals had changed over the years, admitting they are "about one tone lower, perhaps" than in the group's heyday.

However, he went on to promise that the sound fans would hear on the tour would still be "very much ABBA."

Back in 2018, Ulvaeus spoke about the direction of the two original new songs - "I Still Have Faith In You" and "Don't Shut Me Down" - though the band has since reportedly upped the number of upcoming tracks to five.

"One of them is a pop tune, very dance-able," he said. "The other is more timeless, more reflective, that is all I will say. It is Nordic sad, but happy at the same time."

In the interview with The Times newspaper, Ulvaeus also talked about his lasting relationship with his bandmates. "We are really good friends and we see each other quite often," he said. "Being together in the studio again, it was so familiar. It all came rushing back in seconds. We had fun. You have to have fun."