They burst onto the K-pop scene in 2007 in bright, kitschy superhero outfits and took the world by storm with their wildly-infectious retro-pop hit, Nobody.
The song spawned thousands of YouTube covers, spoofs, and remixes from Singapore to China to Japan and even the US, prompting the five-member girl group to go international, leaving the strong support of their local Korean market.
Now back in Asia and here in Singapore after two years to kick off the first leg of their Wonder World Tour, the question on everyone's minds was - do the Wonder Girls still have what it takes?
The answer was a resounding yes for the 4,000 fans who turned up on Saturday night at the Resorts World Sentosa as the Wonder Girls sang, bounced, rapped, and belted their way through a whopping 23-song set complete with eye-catching costumes, quirky graphics, and flashing lights.
But if fans or audience members were expecting the same cookie-cutter, fresh faced K-pop girl group members they used to be, they were in for a shock.
The five women on stage demonstrated spades of confidence and a distinctly edgier sound -- with strong vocals and fiercer dance moves and a clear rejection of the auto-tune quality and military-precision group dances of yesteryear.
From the booty-shaking, street-inspired free style dancing of their hit summer comeback single "Like This" to the stomping beats of "New Shoes" and the stirring soul ballad "Hello to Myself" - the concert felt like one wild Girl's Night Out - by the girls, for the girls.
"I see more girls than guys today," enthused Wonder Girl member Lim in fluent American-accented English, "So this is for all my ladies!"
The Highs ...
In a smart move to re-introduce the girls back into Singapore's mainstream K-pop consciousness, each girl performed a solo, breaking the concert into 5 parts and giving them all a chance to shine.
And shine they did -- rapper and cool-girl Yu Bin wowed with her tongue-twisting rapping on a remix of mega-hit So Hot, while power balladeers Sun and Yenny sang their hearts out on two slower songs, showing vocal prowess that lay mostly buried in the less demanding bubble gum pop tunes they used to sing.
Despite being jet-lagged from flying into Singapore just the day earlier, the energy level was high and the smiles never left the faces of the consummate performers as they interacted with the mosh pit.
Newest (Wonder) girl on the block Lim -- who was brought in to replace Sunmi -- showed that behind that bubbly, chirpy, baby face belied some seriously ghetto dance moves and an in-born ability to rouse crowds with her infectious energy.
The most entertaining moment that night, however, had to be when the Girls sashayed on stage in Singapore girl sarong kebayas, paired bizarrely with brown wicker baskets filled with sweets.
They then proceeded to liberally dispense the candies to the screaming crowd, and to the amazement of the audience, managed to dance to self-penned and produced electro-dance song R.E.A.L despite the obvious .. restrictions of the lower half of the uniform.
Unfortunately, the group was let down by the rather poor sound and lighting at work at the RWS's Compass Ballroom. Several times, the flashing lights strobes shone directly into the view of the fans, causing moments of blindness and obscuring the girls.
The ballads were also often drowned out by the bass beats, resulting in choppy sounds and the girls' voices fading in and out.
(RWS has contacted Yahoo! Singapore to clarify that the audio system and lighting effects had been brought in by an external company contracted by the concert's organisers)
Old is Gold?
Saturday night's concert also saw the unveiling of the Wonder Girl's much hyped comeback single "Like Money", co-produced and featuring American rapper Akon.
Watch "Like Money" below.
The video for "Like Money" showed the girls undergoing a "transformation", emerging as half-cyborgs to perform the fully-English song with lyrics like "I'm not just a girl / I'm more precious than pearls / and I deserve all you got baby."
Despite the Americanised look and feel of the video, it appears that JYP Entertainment, which manages the girls, is sticking to it's tried and tested "catchy dance" formula - as the electro-pop song features synchronized dance routines reminiscent of earlier hits.
And old is indeed gold - the loudest screams on Saturday night were reserved for the almost shamelessly kitschy supergirl themed "Tell Me" and of course, "Nobody" that saw more than half of the audience rising to its feet and clapping as they sang along.
The Wonder Girls represent a new breed of K-pop girl groups -- fluent in both Korean and English and holding their own in international press conferences instead of relying on translators and the stern censorship of strict managers.
Confident of their individual talents and not afraid to show it, they embody girl power in an arena dominated by factory-churned idol groups with bland, pleasant personalities.
Whether their "Americanised" formula will work in the homogenous K-pop industry where a two-year break is the equivalent of career obscurity is anyone's guess.
Watch the Wonder Girls at their kitschy best in "Tell Me" and see how far they've come !