YoonA revealed the behind-the-scenes story of her kiss scene with Ji Chang Wook in 'The K2.'  

She said, "Ji Chang Wook is someone who is good at leading others...When we first met in Spain, we struggled in getting to know each other."

YoonA explained, "Our director said, 'Hurry and become friends since you guys have to shoot a kiss scene soon.' So we talked and got to know each other. Because we had the same goal in mind, after the scene, we became much closer."

She complimented Ji Chang Wook, saying, "He helped me a lot to create 'Anna' (YoonA's character in drama). Whatever acting I did, he would say, 'Do as you like.' He helped with the detailed acting."