Wu rose to fame in South Korea as a member the boyband EXO. He left the group in 2014 to pursue a lucrative acting, modeling and singing career in China.
Du Meizhu (19 years old) accused NetEase, a Chinese news portal, of dating her as a 17-year-old. Du Meizhu, 19, also claimed Wu had sex at least seven other girls younger than her 18 years old, promising fame and alcohol.
Du stated that these include two minors "who don't want to see their lives disturbed, but would like to see him punished."
Wu, who is also Canadian citizen and was raised between Vancouver and Guangzhou, has denied the claims on social media.
He wrote that he had only met Miss Du once, and didn't ply her alcohol. "I have never 'coerced women to sex' or engaged with 'date-rape'," he said on Monday. His studio stated that it was pursuing legal action against the accused.
Kans, a domestic skincare brand, Yunting music streaming platform, and Libai, a household detergent manufacturer, announced that they would end all ties to Wu. Singer has several lucrative advertising contracts with luxury foreign brands.
Du stated that "my life has been completely destroyed." She wrote, "Although my only ever slept in Wu's bed, the public has long believed that I am damaged goods" in a Weibo posting with over 7.3 million likes.
Du, who claimed she wants justice for other victims, gave Wu an ultimatum: quit the Chinese entertainment business within 24 hours, and publicly apologise.
In China, the legal age for sexual consent is 14.
These allegations led to a flood of solidarity among Chinese women. The Weibo hashtag "girls Help Girls" had more than 130m views Monday.
On Twitter, the hashtags "Du Meizhu interview" & "Du Meizhu requires Wu Yifan to announce that he is quitting entertainment industry" received 1.8 billion and 440m respectively.
A few public figures were forced to resign during China's #MeToo movement in 2018, which was started by feminist activists in 2018. This gave women the opportunity to share their stories of sexual assault online.
However, activists claim that China's opaque legal system makes it difficult to seek justice.