Lovelyz's Kei and myunDO dropped a cover of Freestyle's "Y," a track that was immensely popular when it came out back in 2004. 

Kei lends her sweet vocals to the track, perfectly imitating the high tone from the original track yet putting her own color to it, and myunDO lays down the verses, rapping in a calmer, more monotone style. 

Listen to it above!