Although most idols--all celebrities, even--are known for their vibrant, youthful energy as well as appearance, there are a couple who look even more innocent, cute, and younger than their age ('dongan' / baby face), so it comes as a surprise when a fan finds out their birth date!  On the other hand, there are some who look more mature and refined for their age ('no-an'), giving off a sophisticated and classy vibe that could rub off on their appearance and make them look older than they really are.

Either way, whether it's just one or both in the cases below, these idols below are gorgeous in their own right and are sure to raise some eyebrows for those who never guessed that they were born in the same year!  Check 'em out.

SEE ALSO: 20 idols you'd never have guessed were the same age

1986 - Sunny Hill's Misung & Girl's Day's Sojin

1988 - 2PM's Taecyeon & ZE:A's Siwan

1989 - Kim Woo Bin & SHINee's Onew

1989 - EXID's Solji & Girls' Generation's Taeyeon

1990 - SECRET's Hana & Girls' Generation's YoonA

1990 - Hong Jong Hyun & EXO's Xiumin

1991 - B2ST's Dongwoon & BTOB's Minhyuk (1990)

(Those with birthdays late in the year are considered same-age friends as those with early birthdays in the following year.)

1991 - SISTAR's Hyorin & Red Velvet's Irene

1992 - SISTAR's Soyu & Sohee

1993 - Seo Kang Jun & INFINITE's Sungjong