Recently two popular actresses admitted to dating in secret although they would not say whom they dated. On an episode of the KBS show "Happy Together," Gu Hye Sun admitted to dating a fellow celebrity while filming, although she did not say which celebrity or which drama she was shooting.

Early in February Park Shin Hye admitted to dating in secret, saying it was good preparation for her dating behavior in "Pinocchio."

Considering how many couples are eventually "caught" by the camera there may be a whole lot of secret dating going on.

Here are six celebrity couples that did a good job of dating in secret but had to confess they were going out.

1. Won Bin and Lee Na Young dated for a few years before the Korean media outlet Dispatch snapped them leaving her apartment building. The two met when Young joined his agency, Eden Nine in 2011. They were introduced by a mutual stylist and dated for over a year before they were photographed together.

2. The same Korean news outlet revealed that actors Jo In Sung and Kim Min Hee were dating. The actors met through a mutual friend and began dating around the time he wrapped up his role in "That Winter The Wind Blows." They broke up in October 2014.

3. Choi Ji Woo and Lee Jin Wook kept their relationship a secret for two years. The actors met while appearing in the drama "Air City." They broke up shortly after making their relationship public.

4. In May of 2014 fans learned that actors Gong Hyo Jin and Lee Jin Wook had been dating secretly for at least six months. The actors met at a fashion show and again at a New York City film festival. By the time that Gong Hyo Jin finished filming "It's Okay That's Love" she had broken up with Lee.

5. Model-turned-actor Kim Woo Bin dated model Lee Ji Ahn for two years without anyone finding out. The two met on a modeling assignment. Fans learned he was dating Lee Ji Ahn in September of 2013 but did not know the two had broken up until May 2014, four months after the actual split.

6. Lee Bo Young and Ji Sung managed to keep their relationship a secret for three years. The actors met when they appeared in the 2004 SBS drama "Save The Last Dance For Me." They kept their relationship a secret until 2007. Now they are married and expecting their first child.

And some celebrities even get married in secret. That was the case with actress Lee Ji Ah and k-pop icon Seo Taiji. No one knew they were ever married until they were dealing with the ramifications of their divorce.

Are you curious which celebrity Gu Hye Sun dated? Who would you guess it was?