Their characters briefly dated on "I Hear Your Voice" and then wound up being good friends. In real life, Lee Bo Young and Yoon Sang Hyun became such good friends that she asked him to sing at her upcoming wedding. And the way he responded makes it easy to see how much they probably liked to joke around on set.

"Lee Bo Young asked me to sing 'Never Ending Story' at her wedding," said Yoon. "She asked me to sing that song for her parents but I will sing it depending on the way she acts."

Yoon Sang Hyun, who did not make his show business debut until he was 32, initially wanted to be a singer, not an actor. His roles in "Queen of Housewives" and as Oska in "Secret Garden" not only propelled his acting career but also helped launch a singing career. He is now a popular singer in Japan.

He had never acted with Lee Bo Young before although he co-starred in "Secret Garden" with Lee Jong Suk, whose character wins the affections of Lee Bo Young in "I Hear Your Voice."

In the drama Lee Bo Young played Jang Hye Sung, a mercenary lawyer and Yoon played Cha Kwan Soo, a more idealistic lawyer. The two characters did not start out liking each other but came to respect each other and even briefly dated. When it became clear that Hye Sung liked Lee Jong Suk's character, Park Soo Ha, Kwan Soo graciously accepted the situation and the two lawyers ultimately became good friends.

The three actors enjoyed working together. Yoon describes Lee Bo Young as being funny and easy to get along with, a lot like her character in "I Hear Your Voice."

"She has a masculine personality and acts like a male friend," he said. "Most actresses act feminine but Lee Bo Young is very natural and wears comfortable clothes. I have seen a tomboyish side to her that I have never seen in other actresses."

The overall atmosphere on set was very friendly and the two actors became friends much faster than their characters did. After the show ended, most of the cast went on vacation together to Phuket, Thailand.

"Bo Young continuously bought tasty food when we were at Phuket," said Yoon. "Even though she caught a cold and couldn't swim, she took us to many places since she knew the area so well."

Lee Bo Young will marry actor Ji Sung on September 27. Lee Bo Young and Ji Sung met when they appeared together in the 2004 SBS drama "Save The Last Dance For Me." In that drama, Lee Bo Young lost Ji Sung to his leading lady, played by Eugene. They did not admit they were dating until 2007 and she only announced her marriage plans after "I Hear Your Voice" ended.