Take A Chance On Me, Waterloo, Dancing Queen, SOS – the list of Abba’s greatest hits are seemingly endless – and, for the past 20 years, Björn Again have been celebrating the music of the Swedish supergroup.

Björn Again is marking its anniversary with a show at Kew Gardens’ annual Summer Swing festival next week and, with Abba fever stoked by the success of last year’s Mamma Mia! film, tickets are long gone. Those who have been lucky enough to snap one up can expect an evening packed with their Abba favourites, with a few surprises thrown in for good measure.

Rod Stephen, the Australian musician who started Björn Again at the end of the 80s, explains: “The current show is part of our 20th anniversary, which is a celebration of Björn Again and it is also tied up with Mamma Mia!.

“It had some great Abba songs in it which were not hits, including When All is Said and Done, Our Last Summer, and The Winner Takes It All, and we will reflect them in the Kew show.”

Björn Again features four performers who take on the roles of Abba’s Benny, Björn, Agnetha and Frida, with the help of a backing band that Stephen occassionally plays in.

He describes Björn Again as a show rather than a group – he is particularly loathe to label his creation a tribute act.

“It is not just a matter of saying Abba is popular and we put on the costumes and pretending to be them – it is a show that has an identity of its own. There are a lot of elements in there that are synonymous with Björn Again, such as a breakdown section in Take a Chance on Me, when the Benny character grabs the mike and goes into an Eminem-style rap.”

Abba fans will also be delighted to hear Björn Again comes with the Abba seal of approval.

Stephen explains: “When we first toured in Sweden, Benny and Björn asked us to meet them – I thought we would be executed! They were fascinated, though, as Björn was convinced no-one wanted to hear his music ever again.

“I said: ‘You are wrong, people love your songs and we are becoming really popular’.

“You could see the cogs turning in their heads and, the following year, they released Abba Gold and asked us to help them promote it in Sweden.

“They had no idea how popular it would be around the world. More recently, Agnetha came to a show we did in Stockholm and she had a great time dancing around.”

In the past two decades, Björn Again has become a worldwide phenomenon and, with several shows running at any one time, Stephen’s main job is in managing the enterprise. The show has toured across Australia, Europe and America and was recently performed for Russian president Vladimir Putin.

“I hear people talking about Björn Again as if we have taken on Abba’s mantle,” says Stephen. “It is a pretty big ask, and I would never say we are at the same level, of course, but I know it is highly unlikely they will perform live again so the default position for people who want to see them is to consider Björn Again.”

Björn Again with Jive Talkin’s Bee Gees Story, Kew Gardens, July 8, sold out, for information about returns call Kew Gardens on 020 8332 5655 or visit kew.org/swing More music: kingstonguardian.co.uk