The last time 5566 - at one time among Taiwan's hottest boy bands - performed at the Singapore Indoor Stadium was in 2003.

Then, it had five members - Tony Sun, Zax Wang, Jason Hsu, Sam Wang, Rio Peng, all aged between 17 and 27.

Last Saturday, the group returned to the same location, but as a three-piece - with Sun, now 41; Zax Wang, 38; and Hsu, 33.

Peng left the group in 2003 after sustaining a serious injury and Sam Wang is reportedly no longer in touch with the band.

But nostalgia-seekers pining for an evening in the good old 2000s - the peak of 5566's success - were greeted with the surprise appearance of Peng towards the end of the show.

He was even well enough to join his former bandmates to sing and dance to two songs, Doesn't Matter and I'm Sad, both off the group's first studio album in 2002.

Explaining his presence at the show, Peng, now 41, said: "I just want to be with you guys. I'm really very proud of you."

Given the success of the band's four albums and their starring in idol dramas such as My MVP Valentine (2002) and Westside Story (2003), it is not difficult to see why.

I'm Sad, an enduring karaoke favourite said to be 5566's most famous song, was performed a total of three times - including a flashy carnival-esque version - so the band clearly knew what the 8,000-strong audience wanted to see.

And they delivered, taking fans on a trip down memory lane, regaling them with hits such as Love Wander and One Light Year.

While they largely stuck to crowd favourites, the group also threw a medley of covers into the setlist - including Mayday's Party Animal and Jay Chou's Nunchucks - which turned out to be among the evening's highlights.

Time, it seems, has helped the members develop more distinct personalities and each had a segment to sing solo numbers.

Most striking was Wang, with his pink hair, outrageous costumes and outgoing nature. Among the trio, his voice seemed the strongest, doing most of the heavy lifting in the group sing-alongs.

Group leader Sun gave off a quiet confidence in his understated get-ups and reserved manner, while Hsu did most of the rapping and turned on the charm with his megawatt smile and cute dimples.

The band made full use of a gangway that encircled the floor seats, frequently walking from the stage to allow fans a closer look at their idols.

Lasting more than three hours, this concert was essentially fan service. And for one night, it was 2003 again.