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.