Billboard posted its annual list, '21 Under 21', of the hottest 21 stars under the age of 21 who are sure to make it big.

Previously, Wonder Girls and 4minute's HyunA made the list. This year, YG's solo artist Lee Hi just made the list at #20! Check out Billboard's reason for picking her below.

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.

Other artists who made the list were One Direction (#1), Justin Bieber (#2), Miley Cyrus (#3), Lorde (#6), and Bridgit Mendler (#13).  

SEE ALSO: Top 5 K-Pop Concert Essentials!

Congratulations to Lee Hi!

Tip: Ismael D.