My Heart Beats(2011)

Original title: 심장이 뛰네

A poor and lonely English professor, Juri(37), decides to become a porn actor using a mask to hide behind, after she watches an unusual porn, featuring an old and fat woman. And she visits Myungsook, a porn producer, despite their separation of 10 years. After various tests and rigorous diets Juri finally stars in a porn film with an attractive young porn star, Byul(20), who saves money for studies abroad to become a professor. He sports a flawless body except a deep scar across his chest. However on the set, she keeps pushing Byul away, and nobody knows that she is a virgin.