Members of Swedish pop super-group ABBA made a rare appearance together on Wednesday to celebrate the opening of a restaurant in Grona Lund, Stockholm, which was inspired by the group.

All four members - Björn Ulvaeus, 70; Benny Andersson, 69; Agnetha Fältskog, 65; and Anni-Frid Lyngstad, 70 - reunited during the launch of "Mamma Mia! The Party," Ulvaeus' new restaurant, according to the New York Daily News.

The last time that all four members were seen in public was during the premiere of the film "Mamma Mia!" back in 2008.

Fans and guests who went to the opening night of the restaurant, which will also serve as an entertainment venue, paid around £110 ($155) for the ticket, according to The Mirror. The website of the venue states that guests would be able to enjoy a Mediterranean-style buffet while they were watching the show.

"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," the website says. "No evening is like any other and no-one knows how it ends. It all depends on where Abba's songs take us."