As opening day looms, convoys of trucks roll up to the site to deliver the furnishings and items that will make up the collection: flamboyant sequined costumes, gold records, and re-creations of their recording studio and dressing rooms, among other things.

Workers bustle to finish what will be a temple to the creators of some of the biggest hits of the 1970s, including , and , the song that won the band the 1974 Eurovision Song Contest and thrust them on to the international scene.

Through the museum's big windows, passersby can catch a glimpse of a large main room. Few people have been authorised to enter the premises until the official opening. But they have let slip a few details.

For example, fans who dreamed of becoming the fifth member of the band will be able to appear on stage with the quartet and record a song with them thanks to a computer simulation.

And in another room dedicated to the song , a 1970s telephone will be on display. Only four people know the phone number: ABBA members Agnetha Faeltskog, Anni-Frid (Frida) Lyngstad , Benny Andersson and Bjoern Ulvaeus, who may occasionally call to speak with visitors. "It was Frida's idea ... so of course she'll call," says curator Ingmarie Halling.

The museum will pay homage to the music. "We have to have the best isolation in the world to be able to play different music in each room," Hansson jokes.

ABBA last appeared on stage together in 1982, and split a year later. They have repeatedly refused to reunite.

After the split, the band rarely all appeared in public together, so getting all four involved in the museum is a coup.

ABBA has sold more than 378 million albums worldwide, outdone only by Elvis Presley and the Beatles.

The museum's website says it expects to attract a quarter of a million visitors this year.

"It's very exciting," says Micke Bayart, who headed the band's official fan club in the 1980s.

"ABBA is part of Sweden's musical history, it's only right that there be a museum dedicated to them: they deserve it."