Last year Wonder Girls refreshed their throwback-inspired concept, transforming from a '50s Motown sound to a '80s synth-pop band, and for their latest comeback, they've ended up somewhere in the middle. Watch "Why So Lonely" above where Yenny, Yubin, Sunmi and Lim embrace a '70s-inspired rock band look and feel. 

Written and produced by the members, "Why So Lonely" has a reggae-rock sound that's perfect for summer and right on trend as the likes of Fifth HarmonyDrake and Meghan Trainor continue to incorporate island sounds in their pop soundscape. But the surging guitar riffs mixed with Wailers- and Sublime-like ska beats give the track a classic-rock vibe that the ladies successfully pull off as they detail wanting a deep love rather than their current one that makes them feel "so lonely."

The accompanying video is a playful and colorful metaphor on the song's subject matter as the quartet come together to harass their mannequin boyfriend; obviously connecting the useless lover to a hollow clothes model. Together, the girls tie the mannequin up, throw him into the trunk of their car and douse him in silly string and sauces. Throughout it all, they're rocking modern-yet-psychedelic looks that boast touches of the '60s and '70s with the colorful knits, trippy patterns and Lennon-like sunglasses.

"Why So Lonely" is the title track off Wonder Girls' new three-track EP that includes further exploration into sunny ska, featuring the dreamy "Beautiful Boy" and the funky stomper "Sweet & Easy." The WG ladies wrote and produced on every track on the record further showing their progression into artists and away from the manufactured "K-pop idol" tag.

Watch a classic interview from the Fuse Vault with Wonder Girls below where they did the now-classic "Gangnam Style" horsey dance for us: