"I don't know if this is the right place to unveil this, but we're in love", said Hong (56), who filed for divorce from his wife in November. "We truly love each other in our own way",
He was speaking at the Korean premiere of "On the Beach at Night Alone" in Seoul on Monday after Kim won the Silver Bear for best actress at the Berlin International Film Festival last month.
Media speculations about their relationship started after Hong filmed his 2015 movie "Right Now, Wrong Then" with the actress, but neither had so far commented.
"At first, I thought I had no reason to tell this... This is our private matter", the director said when asked about their long silence. Kim (35) also confirmed the relationship, saying: "We love each other with all our hearts. We'll humbly accept everything -- situations ahead of us and that will come".
"On the Beach at Night Alone" is about an actress who goes away to Germany to reflect on her relationship with an older married director.
Asked if the movie is autobiographical, Hong said he had "no intention" of recreating any portion of his life in his films, though he has previously spoken of how he likes to start with a situation that is close to his own biography.
Kim said her work with Hong is "extremely valuable" to her and said she only wants to focus on the work before her.
Subscribe to HanCinema Pure to remove ads from the website (not for episode and movie videos) for US$0.99 monthly or US$7.99 yearly (you can cancel anytime). The first step is to be a member, please click here : Sign up, then a subscribe button will show up.