20. Lee Hi: 21 Under 21 (2013)

Lee Hi

Last Year's Rank: N/A

Birthdate: September 23, 1996 (Age 17)

Why She's Hot: During the past 12 months, K-pop newcomer Lee Hi racked up chart successes rivaling established Korean idols. The soulful vocalist first appeared on the K-Pop Hot 100 in October via a collabo with hip-hop trio Epik High, "It's Cold," a No. 1 hit. Lee Hi followed up with her Duffy-esque debut solo single "1,2,3,4," ruling three weeks atop the K-Pop chart. Fast-forward to March, throwback-inspired LP "First Love" spawned two additional K-Pop smashes: The catchy, No. 4-peaking "It's Over"; and melancholic dance track "Rose," her third No. 1. Plus, the songbird performed with PSY at his Happening Concert, where he unveiled his record-breaking "Gentleman" video.