South Koreans are very particular with age. If you are a woman, you address your older friend "oppa" if he's a man and "unni" if she's a woman. If you are a man, you address your older friend "hyung" if he's a man and "noona" if she's a woman. If you are younger, you are a "dongsaeng." If you are of the same age, you are "chinggus." Usually, you are more comfortable with your chinggus. Thus, this list will try to determine who are the chinggus, the oppas, the unnis, and the dongsaengs.
http://www.ranker.com/list/same-birth-year-south-korean-actors-v1/beegee1,
Cha Seung-won
Jang Dong-gun
Jin-hee Ji
Lee Byung-hun
Lee Young-ae
Park Shin-yang
Ryu Shi-won
Lee Seo-jin
Uhm Jung-hwa
Jung Joon-ho