Facebook has quietly launched a photo-editing app exclusively for China.
The app, called Colourful Balloons, was launched in May and is almost identical to the Facebook Moments app. It was spotted by the New York Times on Friday.
The BBC understands that part of the reason the app was not branded as Facebook was to study how apps organically gain users in China.
Facebook is working with Chinese app developer Youge Internet Technology.
"We have long said that we are interested in China, and are spending time understanding and learning more about the country in different ways," a Facebook representative told the BBC.
"Our focus right now is on helping Chinese businesses and developers expand to new markets outside China by using our ad platform."
The BBC has not been able to confirm whether the Chinese authorities are aware that Facebook launched the app in the country. However, the app works with WeChat, a leading messaging app by Chinese social media giant Tencent.
Twitter was blocked in 2009, and all Google services, including the video-sharing platform YouTube, were banned the same year.
China now has the world's largest online market with 731 million users, according to latest statistics from the China Internet Network Information Center (CNNIC).
Google officially pulled its operations out of China in 2010 as a protest against internet censorship, but is now in talks with Beijing to relaunch its services in the country, according to CNBC.