The 40-year-old gave natural birth to a girl and boy, around 10:30 a.m. at Cheil Hospital, Seoul, her agency Storm S Company announced Monday. The babies are fraternal twins.
"The mother and babies are healthy", said the agency.
The movie star had been off the public radar since starring in Park Chan-wook's 2005 award-winning film "Sympathy for Lady Vengeance", and surprised fans by secretly marrying a Korean-American businessman, Jeong Ho-young, in August 2009.
In September that year, Lee entered Hanyang University to pursue graduate studies and had been working toward a doctorate degree in theater and film.
Last April, the actress made headlines when she and her husband were spotted attending a basketball game in Seoul. The couple was photographed sitting in VIP seats for the Korean Basketball League match between the Ulsan Mobis Phoebus and Jeonju KCC at Jamsil Gymnasium.
Lee rose to international stardom by playing a lady of the court, Jang-geum, in the period TV drama "Dae Jang Geum".
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