Amateur actors Lee Sung Kyung and Nam Joo Hyuk might have found their breakthrough after playing the lead roles in the recently-ended "Weightlifting Fairy Kim Bok Joo."

Despite low ratings, it cannot be denied that the characters of Kim Bok Joo and Jung Joon Hyung have won the hearts of the viewers of "Weightlifting Fairy Kim Bok Joo." However, behind these two characters are two actors who struggled and sacrificed a lot appear as athletes.

In an interview with Korea Times, Lee Sung Kyung and Nam Joo Hyuk shared what they had to go through to play as a weightlifter and a swimmer in the drama series. The 26-actress revealed she had to work hard to gain extra five kilos to fit the role.

However, Lee Sung Kyung admitted that aside from preparing herself to portray the role of a weightlifter, she also spent plenty of time in practicing the emotional side of Kim Bok Joo.

"I focused more heavily on acting Bok Joo's life and emotions so that people could immerse themselves into the story better. I actually lived like Kim Bok Joo," she said during the interview.

Contrary to the actress, Nam Joo Hyuk lost five kilos for playing as a talented swimmer. The actor said he was almost always tired after every filming of "Weightlifting Fairy Kim Bok Joo" that he would rather sleep than eat.

He added that he and Jung Joon Hyung are alike, making it easy for him to play the role. "We are playful and behave naughtily sometimes but we take care of our friends behind the scenes," Nam Joo Hyuk said.

In a separate interview, the actor named Kim Bok Joo as his ideal type, Allkpop cited. Nam Joo Hyuk said he admires girls who give encouragement just like Lee Sung Kyung's character in the drama series.

The 22-year-old actor thought he needs someone who would cheer on him, considering that he is working in the entertainment industry. Nam Joo Hyuk also said he is not after the physical attributes of a person.