Lee Sung Kyung & Nam Joo Hyuk Dating: 3 Clues That Helped Fans Predict Real Life Romance Before It Was Announced

"Weightlifting Fairy Kim Bok Joo" co-stars Lee Sung Kyung and Nam Joo Hyuk have already made an announcement that they are officially dating after the duo were spotted together at the Coldplay concert in Seoul. The private couple has been keeping their relationship a secret for quite some time but there were already hints that the couple was developing romantic feelings towards each other even before the official admission.

According to Drama Fever, Nam Joo Hyuk has been calling Lee Sung Kyung his girlfriend as a joke long before the drama has finished filming. A behind the scenes footage showed the actor introducing Lee Sung Kyung to the camera man as his girlfriend. There was also no sign of discomfort between the two stars when filming their romantic scenes. As a matter of fact, their level of comfort has been one of the main clues that clued fans in on the romance.

It has earlier been reported that Nam Joo Hyuk and Lee Sung Kyung quite easily ad-libbed some of the cute kissing scenes for "Weightlifting Fairy Kim Bok Joo". It was revealed that two of the kisses where Bok Joo was encouraging Joon Hyung to practice was actually a spur of the moment decision on the part of Nam Joo Hyuk, Koreaboo reported.

On the last day of filming, they filmed the proposal scene on the field where Nam Joo Hyuk's character Joon Hyung popped the question to his weightlifter girlfriend Bok Joo, played by Lee Sung Kyung. It was a scene that ended with a very beautiful kiss and a lot of laughter. At the end of the filming, both actors were obviously quite emotional as they were about to part. The fact that the director gave them a makeshift award for doing such a great job brought in the waterworks from the two sweethearts. It may not have come as a surprise to the staff that the pair were already in love in real life.