Joy Chen, a former deputy mayor of Los Angeles, didn't expect to become a popular author in China. Yet she is now in the country promoting her book Do Not Marry Before Age 30.

First published in Chinese in 2012, the book now out in English is being pitched to China's "leftover women", and a movie deal with Wanda Media is also in the works for the Chinese-American author who once was also a real estate developer.

Chen, 47, was also a CEO headhunter.