- Movie: Secretly Greatly (English title) / Covertness (literal title)
- Revised romanization: Eunmilhage Widaehage
- Hangul: 은밀하게 위대하게
- Director: Jang Cheol-Soo
- Writer: Hun (comic)
- Release Date: June, 2013
- Genre: Action / Comedy
- Distributor: Showbox/Mediaplex
- Language: Korean
- Country: South Korea
Three handsome North Koreans spies attempt to live in South Korea as ordinary men. The men are characterized as a stupid man, a wanna be idol singer and a high school student. All three men live in a poor neighborhood in Seoul, South Korea. After two years, they receive an order from North Kore.
- Based on webcomic "Covertness" by Hun (birthname Choi Jong-Hoon). "Covertness" was first published from published June 30, 2010 to May 4, 2011 on Daum website.
- Filming began October 17, 2012.
- Filming ended March 8, 2013. Shooting took 5 months to complete. The last scene filmed took place in an alley in a low income neighborhood. The scene involved Dong-Goo (Kim Soo-Hyun) and Hae-Jin (Lee Hyun-Woo) watching something secretly.
- Kim Soo-Hyun - Won Ryu-Hwan (North Korean spy) / Bang Dong-Goo
- Lee Hyun-Woo - Lee Hae-Jin (North Korean spy)
- Park Ki-Woong - Lee Hae-Rang (North Korean spy)
- Son Hyeon-Ju - Kim Tae-Won
- Kim Sung-Kyun - Seo Soo-Hyuk
- Park Eun-Bin - Yoon Yoo-Ran
- Lee Chae-Young - Ran
- Jang Gwang
- Ko Chang-Seok
- Shin Jung-Keun
- Lee Yeon-Kyung