Actress Ko So Young filmed a documentary on single mothers while pregnant with a second child.

Ko So Young four months ago found out that she is pregnant, but only shared the news with her husband Jang Dong Gun and close family members.

Ko So Young is planned to give a birth to her second child in March or April of next year. However, she still actively participated in filming a documentary on single mothers, tentatively titled, "Mothers Have A Dream Too."

Ko So Young narrates the document and interviews single mothers and their babies.

It was found out that Ko So Young chose not to announce the news of her pregnancy because she did not want her personal life interfering with the work life.

Ko So Young gave a birth to her first child, Joon Hyuk, in 2010.