4minute's HyunA and After School's Lizzy got together during the "2010 MBC Gayo Daejun" to wish eachother a Happy New Year as they both turned 20 years old. HyunA was first to post as she exclaimed,

"We're now 20 years old~~~~? ?? Lizzy, receive good fortune!!!!*^^*"

Soon after Lizzy replied,

"We're now 20 years old~ Happy New Year! Receive good fortune this new year too, HyunA keke"

For those of you who may be confused, in Korea you count your age at the turn of each year. From the moment you are born, you are considered to be one year old and as each new year passes you add another year. Therefore, although Koreans celebrate their birthdays, they consider themselves one year older at each new year. Which explains why HyunA and Lizzy are now 20 years old although their birthdays are in June and July, respectively. Source: HyunA and Lizzy's Twitter