THEY are the Swedish band whose superstardom was sealed by a Eurovision Song Contest before going on to have 25 hit song, including nine number ones.

While officially splitting in 1982, a museum in Stockholm, a theatre production, two movies, and the promise of two brand new songs in 2020, Abba are the band whose legacy refuses to die.

While there is excitement over a reunion, the O2 Arena, a 20,000 capacity arena that the band would have easily sold out during their 70s pomp, has become the venue for a 'thank you for the music' exhibition to Abba, including one superfan's shrine to the pop legends.

Just two months ago the arena became the location for Mamma Mia! The Party - a theatrical and dining experience, already a huge hit in Stockholm.

Now running alongside it at the O2 Arena is Abba: Super Troupers The Exhibition an immersive exhibition which aims to bring to life the world of chart-topping quartet of Agnetha Fältskog, Björn Ulvaeus, Benny Andersson, and Anni-Frid ("Frida") Lyngstad in a visitor experience that charts their music, lyrics, creative process and influence as one of the most iconic pop bands of the modern age.

One of the features is the song that got a lame 'nul points' from the British jury in the Eurovision song contest in 1974.

“If all the judges were men, I’m sure they’d get a lot of votes” – so predicted David Vine, the BBC commentator at the time.

Waterloo would win, become a massive hit, propelled the Swedes to superstardom and a musical journey of eight albums and a legacy that refuses to die.

A replica of the stage used on that Eurovision evening at the Brighton Dome is just one of the features of the exhibition that includes artefacts, photos, videos, interviews, costumes and private letters, many of them going on display for the first time.

Personal items such as member Bjorn Ulvaeus' school report as well as pictures, gold discs and clothing are on display'

Fifty-six-year-old fan Andrew Boardman's shrine consists off hundreds of items of memorabilia he collected for more than 40 years, including cushions, scarves, badges and even Christmas decorations, are also included.

"I have a vague memory of them winning the Eurovision Song Contest but in '75 when 'I do, I do. I do' came out, there's something unique about the saxophone intro that caught my ear and it wasn't too long until I related the two together," said Mr Boardman, whose 2,500 pieces of memorabilia also includes singles, albums, cassettes, videos, DVDs, posters, magazines, colouring books, games and dolls.

He soon got morning and evening paper rounds for money to spend on anything Abba-related he could get his hands on. And he has never stopped.

When video recorders came in, his mum would shout “they’re on”, and he would run down to tape any Abba TV appearance.

"Just every bit of pocket money (went towards buying Abba memorabilia). Everything has gone on and on. As I started to work, it has got bigger and bigger.

“It has been my life’s passion, you could pick any item and I could tell you where I got it, when I got it.”

A look at the lives of the band, pre-Abba, includes displaying personal items from each musician's youth including Björn's school report, his military book and photographs from his time in service, and pictures of a 13-year-old Frida in a jazz band as a beatnik teenager.

Abba's Frida Lyngstad said:"We are delighted to support ABBA: Super Troupers The Exhibition at The O2 following the overwhelming response to our earlier exhibitions in London.

"From our Eurovision Song Contest win in Brighton in '74 to the present day, the UK has long held a special place in Abba's heart, and we have always strongly felt the love and support of our British fans."

Curator Jude Kelly said: “I‘m looking at the progress of a band that worked together from 74 to 84 and produced a body of music that has endured across the world.

“What is it when artists get together and something very special happens? The circumstances of the time, the place and the people. The context of culture has always fascinated me.

"What’s so extraordinary about Abba is that they are inter-generational.

“This is an exhibition of a scale that you rarely see of everything that Abba have ever done. So if you’re at all interested in popular culture, or you love Abba a lot, it’s worth the journey.”

Björn Ulvaeus has previously told about the "fantastic" global reaction to the promise of two brand new songs. And he has said they have been been recorded for release next year.

The band were approached by Simon Fuller, the man behind Spice Girls about creating computer generated copies of Abba or Abbatars for a video instead of the band themselves.

The band then thought they should have something new to sing as well and got into the studio for the first time in almost 36 years.

"Oh yes, it just took virtually seconds. We were standing in front of one of those sound desks in the control room, the four of us, and we were just kind of looking at each other," said Mr Ulvaeus in September.

"It's definitely ABBA sound. That hadn't gone. The minute the two ladies started singing together in the studio, ah, there it was! The same sound," he told Smooth Radio.

"It's slightly lower now because everyone [has dropped] in range. But the sound is the same and yeah, it's going to sound like Abba definitely.

"One of the songs is more timeless, not of a certain style. The other one is perhaps a little nod to the 70s, but with modern sounding instruments. It will be released together with a video of the Abbatars. It's completely new."