ABBA Voyage’s shows began last May, featuring hologram performances by the artists in a tailor-made east London venue.

And despite never seeing the musicians in the flesh, the east London events have drawn huge crowds and rave reviews.

The shows feature three-dimensional digital avatars of the four original ABBA band members singing classics like “Fernando” and “Dancing Queen.”

The motivation behind bringing the Swedish quartet to crowds in their 1970s glory is simple: The members are now much older, and didn’t tour much even as younger artists.

The bottom line

Given the sophisticated technology involved in running each concert, the whole venture was (unsurprisingly) an expensive undertaking.

Before its first-ever show, costs had already piled up to £140 million ($176 million), Bloomberg reported, making it the most expensive in music production to date.

But the show has fared well so far—most of the concerts run full, Bloomberg reported, and loyal fans continue to flock in big numbers to watch ABBA’s digital re-creations.

The virtual reality concert had already sold 1.6 million tickets, the project’s lead investor, Pophouse, revealed last week.

With an average ticket price of £85 ($105), the Swedish band’s concert is estimated by Bloomberg to rake in $2 million each week—over 15 months, that’s amounted to $150 million.    

“It was meticulously prepared, enormously expensive and incredibly difficult to create believable digital people,” said Svana Gisla, a producer of the concert, told the Guardian earlier this year. “But the result is magical.”

Producers of ABBA Voyage are reportedly looking to expand the tour to other cities like New York and Singapore. It’s also set to continue running in London for the foreseeable future. 

Here we go again

Even though ABBA’s music is more than four decades old, the pop group has managed to stay relevant courtesy of a stage adaptation and movies named Mamma Mia—which its songs inspired.

Advancements in music technology served as an opportunity for ABBA to make its comeback, without having to undertake an actual tour following its breakup.

“ABBA has done it again,” Pophouse CEO Per Sundin told Bloomberg. “They were early to music videos, they were early to jukebox musicals.” 

Representatives at ABBA Voyage and Pophouse didn’t immediately return Fortune’s request for comment. 

Concert business and big money 

It’s an open secret—concerts make a lot of money for artists. This year has been dominated by the concerts of two big pop icons—Beyoncé and Swift, partly because it marked the return to full-scale world tours after years of no such activity due to the pandemic. 

Estimates show that Beyoncé could make as much as $2 billion from her Renaissance tour, which started in May and is slated for 57 shows globally. For Swift, the estimate is roughly $1.62 billion by the end of the Eras tour. 

Concerts are a novelty for some artists, which helps explain why scores of fans travel from all over the world to catch them performing live. This interest often boosts economic activity in industries including travel and hospitality.

One example of this was the so-called “Beyoncé blip,” a phenomenon observed in Sweden where prices of hotel rooms and other recreational activities rose in the lead-up to Beyoncé’s Stockholm concert. 

It’s unclear how much each of the four ABBA band members make from their virtual shows in London. But for a concert that doesn’t need its artists to physically perform each night, ABBA Voyage is making a killing.