Which girl group makes Kim Hyun Joong's heart flutter?

Singer Kim Hyun Joong has revealed which female idols make his heart flutter. While guesting on SBS Power FM's 'Jung Sun Hee's Night Like Tonight', DJ Jung Sun Hee asked, "Pick a girl group that warms your heart." Kim Hyun Joong responded, "During one broadcast rehearsal, I saw one of A Pink's members practicing on stage in her school uniform. That was really cute and warmed my heart." Kim Hyun Joong also grabbed interest for choosing 2NE1's "I Am The Best" as the song that he's been listening to the most lately. He stated that he gets strength when he watches 2NE1's performances and he thinks that they are a cool group. Additionally, Kim Hyun Joong also confessed, "My last relationship was five months ago." Source: Newsen via Nate