Sadly for Abba fans, however, Benny Andersson, Björn Ulvaeus, Anni-Frid Lyngstad, and Agnetha Faltskog weren’t in the mood to sing any of their signature hits at the Stockholm event.
They also arrived and left separately and declined to be photographed together on the red carpet, though they stood beside one another on the stage.
In 2014 Benny Andersson said he didn’t rule out the possibility of an Abba reunion, but when questioned by reporters in Stockholm he insisted that he didn’t think the four of them would be getting back together to perform.
“We are here to party,” added Björn, who is the brains behind the new restaurant inspired by the venue in the hit 2008 movie Mamma Mia.
Fans and guests paid $220 for a ticket to the opening night celebration.
The venue’s website says punters would enjoy a Mediterranean-style buffet while a show (sans Abba) takes place.
“Everything happens on a magical evening in several acts filled with singing and dancing, daredevil stunts, Greek Gods, flirty waiters, and perhaps a zorba and an ouzo or two,” it says.
“No evening is like any other and no-one knows how it ends. It all depends on where Abba’s songs take us.”
Since officially splitting up in 1982 after both sets of spouses divorced – giving rise to melancholic pop classics like The Winner Takes it All – the Abba members have enjoyed a lucrative afterlife.
Their compilation Abba Gold, released in 1992, is the second-highest-selling album of all time in the UK and has sold 29 million worldwide.
The smash musical Mamma Mia!, which employs many of their hits, has grossed some $2 billion since its debut in 1999, and only recently completed its Broadway run.