But what began as a one-off concert soon became a full-time band.
The production celebrated its quarter-century last year with a series of special events including a one-off concert at the O2.
They also played a solo one-off concert in Portsmouth.
On March 7, 2007 however, the duo played a one-off concert in Mexico City.
It was also announced that special one-off concerts were in development for the near future.
"Fantasi" became a hit once again and together they made a one-off concert in Stockholm.
Although it was originally planned as a one-off concert, numerous American and European dates followed thereafter.
The celebrity had been invited to celebrate her 41st birthday on the island, in return for taking part in a one-off concert.
Michael said that there was no truth in speculation the group would reform for a one-off concert.
In 1997, 2007 and 2009 the original members reformed for one-off concerts in Melbourne.