What have Abba been up to since their 1982 split?
As Abba record their first new material in decades, John Meagher describes the very different paths the band members have taken since they last played together in 1982
For a group that dominated the 1970s and sold stupendous amounts of albums, Abba's final public appearance could hardly have been less auspicious. The occasion was Noel Edmonds' TV breakfast show in December 1982, and his soft-focus interview seemed to embarrass the quartet.
In the cringe-making finale, the host asked them to sing Thank You for the Music and invited a competition winner to join them around the piano as the credits rolled.
There had been much talk for the preceding three years about how long Abba would continue, considering that the marriages of Bjorn Ulvaeus and Agnetha Faltskog and Benny Andersson and Anni-Frid Lyngstad (aka Frida) had ended.
This fuelled some of their most affecting, bittersweet songs, and most fans imagined they would continue to release huge-selling albums well into the 1980s.
They had begun the decade in impressive fashion by releasing The Visitors, now considered by many Abba enthusiasts to be their best, most varied and most consistently strong album.
But the business of being together for long stretches of a time proved insurmountable as, presumably, did any pressure to perform songs written by the men in which the female singers seemed to have come out second best.
There was no grand announcement of a split; they simply stopped working together and would not enter a studio together as a quartet until the summer of 2017 - a fact that took the world by surprise when it was announced by Andersson and Ulvaeus last weekend.
Two new songs have been recorded, both of which are likely to be part of the set when digital hologram versions of Abba tour the world next year.
The news shocked even the most devoted aficionado, because it always seemed that Abba would never record together again. In 2000, they reportedly turned down a billion-dollar offer to reform for a world tour, but now Ulvaeus was talking about the new studio sessions being a "joyful" experience.
Since originally parting company, each member has had remarkably different experiences, cosseted by the fact that having sold so many albums - an estimated 250 million by the time they had called it a day - none ever had to worry about money again.
Andersson and Ulvaeus had talked about writing a musical while still in Abba, and they drew on the Cold War when they teamed up with Tim Rice for the heavily promoted Chess, which finally opened in 1986.
The subject matter was not surprising, given that the title track of The Visitors alluded to oppressive conditions behind the Iron Curtain. But despite a lengthy run in London's West End, it wasn't the smash that its creators might have imagined.
It was also so different at the end of the 1990s when the pair licensed Abba songs to the makers of Mamma Mia! An instant success, it has become one of the highest-grossing productions in theatre history.
The genesis of the idea came from the largely forgotten American movie, Buona Sera, Mrs Campbell, released in 1969. A naff comedy-of-manners starring Kojak actor Telly Savalas, it centres on a woman in wartime Italy who, driven by dire circumstances into prostitution, tricks three of her American GI clients into financially supporting her daughter by telling each of them that he is the girl's father.
Twenty years later, the men return to her village for a reunion with a daughter each believes is his, and our industrious heroine resorts to all manner of hilarious tactics to ensure that her secret does not unravel.
Eighteen years on, the film would inspire jobbing English playwright Catherine Johnson, who had been approached by veteran musical impresario Judy Cramer to write a musical based on the songs of Abba.
In Johnson's version, the story concerns a Greek bride-to-be whose quest to discover the identity of her real father brings three men from her mother's past back to the island they last visited 20 years ago.
It features 22 different songs from the Swedish pop icons' vast repertoire.
The musical has become a bona fide global phenomenon. Since its debut in 1999, 30 million people have seen it and sung along to Abba's songs.
It has made $2bn at the box office and played in 160 cities around the world.
The musical also spawned the hit movie of the same name, starring Meryl Streep and a singing Pierce Brosnan. A follow-up film - which will be both a prequel and sequel to the original - is set for release this year. It boasts a blunt title: Here We Go Again.
Despite their phenomenal money-making ability, Andersson and Ulvaeus stayed largely out of the limelight, although both frequently turned up for Mamma Mia's opening night in various locations. In later years, Andersson, who wrote the music, while Ulvaeus looked after the lyrics, has been the busier of the two and, last year, he released an album, Piano, on the respected classical music label, Deutsche Grammophon. The album featured reinterpreted Abba songs performed on his grand piano.
The post-Abba experience of Faltskog and Lyngstad could hardly have been more different and, one senses, both were glad to escape the spotlights.
Frida, two divorces down, was married to the Swiss-born Swede, Prince Ruzzo Reuss von Plauen, until his death from cancer in 1999. She now lives in Switzerland with her British partner, Henry Smith, 5th Viscount Hambleden.
A strict vegetarian, she was back in the Swedish charts at the end of the 1990s with her Wonderful World duet with Roxette's Marie Fredriksson. She has financial involvement with Mamma Mia! and used to attend the premieres in its early years.
For Agnetha, her marriage to a surgeon ended in divorce in 1992. She made three solo albums before becoming a recluse on an island near Stockholm. Her daughter, Linda (the subject of their parent-child ballad Slipping Through My Fingers), has appeared in a musical written by her father (Bjorn) and Benny.
And in a plotline straight out of a movie, she entered into a relationship with a Dutch stalker, Gert van der Graaf, who had pestered her for years, only to have a restraining order placed on him when the affair ended.
Until recently, she made very few public appearances, earning a reputation as a modern-day Greta Garbo, but that changed in 2013, when she recorded a critically acclaimed solo album, A, which featured such contemporary singers as Take That's Gary Barlow.
Today, Abba are regarded as one of the best pop acts of all time, but they weren't always regarded so fondly.
After fading from view in the early 1980s, they suffered a lean period in the affections of critics and the general public.
For many, they were little more than an embarrassing remnant of the previous decade - a garishly clad quartet who released some decent tunes, but also committed such sonic abominations as Dum Dum Diddle to tape.
The rehabilitation would commence in the early 1990s thanks to the release of the Abba Gold compilation - one of the best-selling albums of that decade - the Abba-referencing Muriel's Wedding and as a result of such disparate names as Kurt Cobain and Erasure bigging up their music. They remain one of the biggest-selling heritage bands in the world, shifting more than two million back catalogue albums every year.
Despite their fabulous wealth and Frida Lyngstad's marriage into royalty, the four are said to be unusually grounded.
Perhaps it's down to that Scandinavian concept of janteloven - societal 'rules' that favour the collective over the individual and shun ostentation.
Rock fans may have pooh-poohed their sound at a time when punk was changing everything, but with disco providing the soundtrack for so much of the population at the tail-end of the 1970s, Abba's power would endure.
Ireland's leading promoters, MCD and Aiken, will be keen to bring the hologram version of Agnetha, Benny, Bjorn and Anni-Frid to Belfast and Dublin when details of the tour are unveiled later this year.