Before Psy, there was the Wonder Girls. The girl group was the first indication that K-pop could become a "thing" in America when their super-catchy, retro-tinged single "Nobody" crossed over in 2009, making the gals the first K-pop act to land a hit on the Billboard Hot 100. Despite being icons in Korea, the ladies pushed on with various degrees of success overseas until quietly announcing a hiatus after releasing their last album in 2012.

But the time off has led the Wonder Girls to refresh the act and the sound. Original members Sun and Sohee have left the group, but Sunmi (who left in 2010) is back, making the act a quartet. Not only that, but the team is showing their musical talents by becoming a legitimate band-band for new single "I Feel You."

The comeback single is an '80s-inspired, synth-pop spectacular with all the marking of a rock hit from the time. There's booming drums (played by rapper Yubin), a Eurythmics-like dance breakdown and, yes, even a keytar. The accompanying video looks like something played on the good days of early MTV as vintage-looking clips are spliced in between the girls rocking out in retro swimsuits.

It's an excellent comeback from the Wonder Girls, who prove that they can still keep their throwback sound, but do so in a totally refreshed way, making them just as exciting as ever. Welcome back, girls.