Four days after the concert, I catch myself humming Mamma Mia.

My wife tells me to quit singing ABBA songs.

It's getting on her nerves.

But I can't help myself. The tunes are so catchy that they are contagious.

Of course, it's an aberration.

I don't even like ABBA.

I'm old enough to remember when they won the Eurovision Song Contest in 1974. Waterloo was a rocking, upbeat number, and the girl singers were beautiful and sexy.

One was blonde, the other brunette - although I couldn't for the life of me name them. Over the following eight years, ABBA became superstars.

I remember their appalling glam-rock fashion sense.

Their music videos were memorable and groundbreaking, but I never bought an ABBA album. I would have laughed at the idea. They were far too cheesy and mainstream, and I regarded their music as pure schmaltz.

So why on earth am I humming their tunes now?

The reason is that an ABBA bandwagon rolled into Beijing one evening last week and won over new fans, including me.

ABBA The Show is billed as the "Ultimate Tribute to ABBA", the '70s band that was once Sweden's biggest export earner after Volvo.

A crowd of about 2,500 - mostly young Chinese - partly filled Beijing Workers' Gymnasium.

Most of them weren't born when ABBA was at the height of its fame.

But some, like my colleague Wei Wei, had seen Mama Mia the stage show with the original West End cast when they appeared in Beijing two years ago. I imagine many in the audience last Friday had seen Mama Mia, the movie.

The audience seemed subdued at first but soon warmed to the look-alike performers. By the end of the 90 minute show, many fans were on their feet swaying, waving and dancing.

What is ABBA's enduring appeal?

Of course it's the music. They wrote some great pop songs and performed them slickly.

ABBA The Show reproduces the super group's trademark "wall of sound".

The band consists of 12 musicians, including two of Abba's original lineup. Saxophonist Ulf Andersson, 65, is the spitting image of former US president Jimmy Carter. But unlike Carter, Andersson can blow a mean horn.

Guitarist Mats Ronander, in horn-rim specs, adds some classic and classy ABBA licks. When he's not playing with ABBA, the Show, Ronander fronts Swedish group Stockholm Stoner.

And then there were the girl singers, who were the stars of the show. Katja Nord and Camilla Dahlin may not be as tall or as pretty as the original group members Agnetha Faltskog (the blonde) and Anni-Frid Lyngstad (the brunette), but these look-alikes can belt out the songs and work an audience.

Hit followed hit at breathless pace, from Voulez Vous, to Knowing Me Knowing You and Money Money Money.

Waterloo was the opportunity for the female string section (three violins and a cello from the London Symphony Orchestra) to cut loose.

Like the originals, the girls smooched with their respective "husband" look-alikes, Benny on keyboards and Bjorn on guitar.

Bjorn, by the way, wore sparkly bellbottoms and sported a blond, pudding-bowl barnet that reminded me of the late Brian Jones of the Rolling Stones.

The band rounded off an enjoyable evening with Thank You for the Music and finally Happy New Year. They went off to resounding applause and didn't reappear for an encore.

Abba, the Show has toured more than 35 countries and played to more than 2 million people.

I'm wondering that maybe they can't get the tunes out of their heads, too.