The South Korean girl group has cracked the Billboard 100 charts – and toured with the Jonas Brothers
Credit: Jeffrey Mayer/WireImage

Wondering who The Wonder Girls are? Already a pop phenomenon in Asia, the South Korean pop quintet – which includes members Sun, 20, Yenny, 20, Mimi, 17, Yubin, 21, Sohee, 17 – is making a splash in the U.S. with their infectious bubblegum pop tunes.

Their first single titled “Nobody” landed on the Billboard Hot 100 Singles chart, making them the first group from South Korea to make such a mark in the U.S. But tween girls know them as the group that shared the stage with the Jonas Brothers this past summer.

Here are five fun facts about these five fresh-faced females:

1. They’re tight with the JoBros:
The girl group lived the dream of tween girls everywhere: They spent almost two months with the Jonas Brothers as their opening act for the U.S. leg of their 2009 world tour. The girls bonded with the brothers on the road to the point that Joe has been spotted wearing the Wonder Girls shirt, and on Sun’s birthday in August, the rock trio bought her a cake (cue adoring sighs). At the time, Sun tweeted, “The guys came to me and wished me a happy bday w/a gorgeous cake! Thank you to the Jonas Brothers for making my bday so special!!”

2. Their manager was a ’90s megastar:
The man behind the group is a star in his own right. Singer-songwriter J.Y. Park became a K-pop sensation in the 1990s, releasing seven albums. He later opened an intensive music school called JYP Academy in Seoul where all five Wonder Girls studied before forming the group.

3. They are reality TV veterans:
The girls have already conquered the small screen. MTV Asia created a reality show about them called MTV Wonder Girls, which followed the group in their everyday lives. Also, Sun was the winner of the Korean equivalent of American Idol called Special Project: Developing a Genius before joining the Wonder Girls as the group’s de facto leader.

4. They started an online dance craze:
Their popularity in Asia peaked when the video for their 2007 single “Tell Me” sparked a viral dance craze and inspired fans began to post their own renditions of the moves.

5. Yes, they like dressing alike:
With their ’60s style bobs and doo-wop wardrobe, these sweet-faced girls embrace a retro-Motown vibe. The band told that their main fashion inspirations are timeless style icons like Twiggy to Audrey Hepburn.