The four former members of Swedish band ABBA, whose catchy tunes still have fans dancing around the world decades after their release, reunited - albeit very briefly - for the opening of a new restaurant-entertainment venture in Stockholm.

Agnetha Faltskog, Bjorn Ulvaeus, Benny Andersson and Anni-Frid Lyngstad all made it for the opening of Mamma Mia! The Party, in which a restaurant at Grona Lund amusement park has been transformed into a Greek taverna as seen in the "Mamma Mia!" musical and film, both filled with ABBA songs.

The foursome, known for a string of 1970s and early 1980s hits such as "Waterloo", "Dancing Queen" and "Take A Chance On Me", split in 1982. They are rarely seen all together these days and have ruled out a reunion.

"We're here to have a party as everyone else," Ulvaeus said on arrival at the Wednesday night opening.

"Appearing together? I don't think so. No. And I expect the others have answered the same thing to that question right? I hope so. Otherwise there will be headlines tomorrow".

While they arrived separately, the foursome later came together on stage inside the restaurant for a brief period to wave to fans and pose for pictures, according to local media posting diners' videos and photos online.

"It will be lovely, I'm sure. I think I've heard them before," Faltskog said on arrival when asked about how she felt about hearing ABBA music again.

Ulvaeus is executive producer of the venture, which he said borrowed the mood from "Mamma Mia!" but not the plot, with guests treated to a Greek-style party full of ABBA songs.

"At the end of the show they (audiences) are very happy," Ulvaeus said, referring to the musical.

"They're standing up in the aisles dancing and the idea was to try to take that with us into a restaurant environment ... and have a really good party with good food, wine and singing and dancing."

According to the restaurant's website, "Mamma Mia!", which was written by British playwright Catherine Johnson and premiered in 1999, has been seen by more than 60 million people. Meryl Streep and Pierce Brosnan starred in a 2008 film based on the musical.

(Reporting By Ilze Filks in Stockholm; Writing by Marie-Louise Gumuchian in London Editing by Jeremy Gaunt)