ABBA fans have been holding out hope that the 70's Swedish super group might someday reunite, and while they have repeatedly ruled out the possibility of touring together, all four band members have reunited for a new business venture.

Benny Andersson, Anni-Frid Lyngstad, and Agnetha Faltskog and Bjorn Ulvaeus were in the Swedish capital of Stockholm for the launch of a dining-entertainment venue called Mamma Mia! The Party. Based on the Greek taverna featured in the Abba-themed film Mamma Mia! it's the brainchild of Bjorn Ulvaeus.

In April 2015, Ulvaeus, 69, sent fans into a frenzy after revealing a new website titled Mamma Mia! The Party. Hinting at the project he told The Local: "I've been working on this experiment for quite a while now and it's actually starting to feel ready." Giving little away, he added that he is creating a "new entertainment experiment that I will tell everyone about on Wednesday". The website featured a teaser film, which sees the star daubing the project's name in blue paint, followed by the infinity symbol.

A year later and the mystery behind the website was revealed, as the Swedish stars joined forces to attend the opening night at the Tyrol restaurant in Grona Lund, Stockholm, on Wednesday, posing together in front of 130 guests, who had paid $150 for the rare privilege.

And while they arrived at the event separately and declined to be photographed together on the red carpet, they did briefly share the stage assuming their original line-up, much to the delight of the cheering crowd.

Describing the dining experience, the venue's website says patrons will enjoy a Mediterranean-style buffet while the show 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. No evening is like any other and no-one knows how it ends. It all depends on where Abba's songs take us."

Asked by reporters if the business venture was the start of a reunion Andersson insisted that he didn't think the foursome would be getting back together on stage to sing. "We are here to party," added Björn Ulvaeus.

Benny Andersson, Anni-Frid Lyngstad, Agnetha Faltskog and Bjorn Ulvaeus AFP/Getty

ABBA became one of the most commercially successful acts in the history of popular music, topping the charts worldwide from 1975 to 1982. ABBA disbanded in 1982, but their legacy remains. In the last 42 years, the group have sold 300 million albums and been inducted in the Rock and Roll Hall of Fame and their songs have inspired a stage musical which has grossed some $2bn since its debut in 1999, and won them a new generation of fans around the world.

The band were reportedly offered $1bn to reform and go on a world tour, and while they have said they will never tour again, they have not ruled out the possibility of recording together. The four Abba stars were last seen in public together for the film premieres of Mamma Mia! in London and Stockholm in 2008.

And while their meeting over dinner wasn't quite the ABBA reunion everyone is hoping for, Twitter, was flooded with ABBA fans reveling in the rare moment that saw the Swedish stars sharing the same stage again.