Image copyright Getty Images

When Japanese actress and former porn star Sora Aoi announced her marriage online, it set off a frenzy on Chinese social media.

That's because she has played a surprisingly significant role in the lives of a generation of young Chinese internet users.

On New Year's day, Ms Aoi posted a picture of her engagement ring on social media and announced the happy news to her fans around the world. Within 48 hours, the post got more than 170,000 comments and 830,000 likes on Weibo, the Chinese version of Twitter.

"We grew up with your movies and will support you as always," said one fan.

Another Weibo user said: "You will always be my goddess… I wish you happiness."

'Teacher Aoi'

Ms Aoi started her career in pornography in the early 2000s. It is estimated that she had starred in more than 90 adult films, with new work being published every month between 2003 and 2005.

Pornography is illegal in China, but that didn't stop Chinese men going crazy for her.

"To many Chinese men who couldn't get proper sexual education in their adolescence, Sora Aoi became our teacher," 27-year-old "Liu Qiang" (not his real name) told the BBC.

Image copyright Weibo Image caption Ms Aoi announced her marriage on Weibo

Her popularity in China soared at a time when the Chinese internet was developing at breakneck pace. New web portals, online communities and streaming sites emerged one after another, facilitating the spread of all kinds of information - including illicit pornographic materials.

Mr Liu used to watch and share porn featuring Ms Aoi using MP4 players with friends when he was in high school. But as technology evolved, they turned to streaming websites to watch porn, as it was "much easier".

"Sora Aoi seized the right time to rise in China", says Prof Wai-ming Ng from Chinese University of Hong Kong's Department of Japanese Studies.

"When she became popular in the country, China was opening up to the outside world in various ways, including in terms of sexuality."

Image copyright CNS Image caption Fans rushed to see Ms Aoi when she attended a marketing event in China

Porn is a key source for information about sex for young people in China, as sex education is limited at school; and most Chinese parents shy away from teaching children about sex.

During a study conducted by Peking University in 2009, more than 22,000 questionnaires were distributed among young people aged between 15 and 24. They were asked to answer three questions on reproductive health - but only 4.4% of participants managed to answer all the questions correctly.

The researchers also noted that many young people learn about sex "by themselves".

But Li Yinhe, China's first female sexologist, cautions against porn being used as a tool of sex education.

Porn depicts sex in an exaggerated way, and some men may be "misled" as they compare themselves to porn actors, Ms Li told the BBC.

Experts have also argued that porn can distort young people's attitudes to sex, or contribute to sexual health problems.

'The Night of Sora Aoi'

With so much porn freely and readily available, what made Ms Aoi stand out?

Sex remains a taboo subject in Asian societies, but Ms Aoi said she "never looked down on herself" because of her career in pornography.

Image copyright Getty Images Image caption Ms Aoi has learnt Chinese calligraphy

She always said she "enjoyed her job" because she could go abroad and speak to fans around the world.

Even when faced with disparaging comments online, Ms Aoi responds politely and with warmth, and her openness and frankness have helped her earn respect and appreciation from fans.

Ms Aoi opened her Twitter account on 11 April 2010. The news spread to China, where Twitter is banned, prompting a flood of Chinese fans to scale the Great Firewall of government censorship by using VPNs to follow her.

That night was later dubbed "the night of Sora Aoi" by Chinese fans.

Seven months later, Ms Aoi opened an account on Weibo, China's Twitter-like microblog. She has earned more than 18 million followers so far - more than the likes of Taylor Swift and David Beckham.

Ms Aoi formally retired from pornography in 2011, reinventing herself as a proper actress and singer.

She released music singles and has landed roles in online videos and movies - and China is a huge market for her.

She appears to have put a lot of effort into familiarising herself with Chinese culture. Every post on Ms Aoi's Weibo is written in Chinese by herself, her manager told the BBC.

Apart from the language, she also started learning Chinese calligraphy. In 2013, a piece of her calligraphy was said to have been sold at 600,000 yuan ($92,000; £68,000).

'Belonging to the world'

It seems paradoxical that Ms Aoi is widely adored by Chinese fans, given the tumultuous relations between China and Japan.

There is longstanding bitterness in China over Japanese brutality during World War Two, and the countries remain in dispute over a group of contested islands known to China as the Diaoyu and to Japan as the Senkaku Islands.

But Wenwei Huang, a Chinese writer who lives in Japan, thinks Ms Aoi has actually played a mitigating role in the civil relations between China and Japan.

"There was once a popular saying on China's internet - 'Diaoyu Islands belong to China, and Sora Aoi belongs to the world'. This is how she relieved the political and civil tensions."

Prof Ng says the Sora Aoi phenomenon in China is a symbol of how, in the age of globalisation, the way people define themselves is not only shaped by nationalities - but by consumption of media content as well.

"For people who like Sora Aoi, no matter which country they are from, they would all feel like they belong to the same group."

Perhaps Ms Aoi serves as a reminder to young people across Asia - despite different nationalities or political views - that they have more in common than they realise.