On December 23, girl group tripleS introduced its 18th member, Joobin. 

Born on May 11, 2006 of Korean nationality, Joobin's full name is Doo Joobin.

The rare and unique family name soon garnered interest among fans, who began investigating whether or not the family name 'Doo' actually existed. A netizen who went to school with Joobin eventually confirmed that 'Doo' was the idol's real family name.

With approximately 5,000 Koreans having the family name 'Doo', Joobin officially joins the growing list of K-Pop idols with quite rare and unique last names!

International fans may be familiar with some of the most common Korean last names, such as Kim, Lee, and Park. Currently, among the list of K-Pop idols with quite unique last names are: Boo Seungkwan of Seventeen ('Boo' is a family name originating uniquely from longtime residents of Jeju Island), Dong Youngbae or Big Bang's Taeyang (there are only around 5,000 Koreans with the family name 'Dong'), Ho Hyun Joo or Jessi (there are around 4,000 Koreans with the family name 'Ho'), Seok Rak Won of ATBO (this family name is generally more common among Koreans, but there are very few celebrities with the name), and still considered the rarest last name of all with less than 1,000 Koreans sharing the name, Ong Seong Wu. 

Can you think of any other celebrities with the family name 'Doo'?