Nine days ago, X-Men star Fan Bingbing – one of China’s richest and most famous stars – turned 37, but only a handful of notables sent greetings on line.

It was a stark break from the past when her birthday celebrations were lavish, well-attended affairs. Last year, Fan’s birthday was marked by a public marriage proposal from boyfriend Li Chen.

This year, she is at the heart of a mystery which is gaining international traction.

For nearly three months, the star – whose Beijing management office is dark and abandoned – hasn’t been seen or heard from in public in any verifiable way.

For a rising Hollywood actress, Fan’s vanishing is stunning, coming amid vague allegations of tax fraud and possibly other infractions that could have put her at odds with Chinese authorities.

Fan’s disappearance four months after her star turns on the red carpet at Cannes in May has already taken a toll on her lucrative sideline as brand ambassador, throwing those companies’ plans into disarray.

Australian vitamin brand Swisse issued a statement saying it was suspending use of her image and “continuing to monitor the situation and hope that it is resolved in the near future”.

Meanwhile, Fan’s whereabouts or fate is unknown.

The star of dozens of movies and TV series in China, Fan is best known internationally for her role as Blink in 2014’s X-Men: Days of Future Past and a cameo in the Chinese version of Iron Man 3.

Fan Bingbing as Blink in X-Men: Days of Future Past. Photo: IMDB

Fan pulled down tens of millions of dollars for her roles, along with handsome sums in appearance fees and product endorsements. Some of those contracts may have landed her in hot water with the authorities.

Fan’s name has been mentioned in reports about a reportedly common entertainment industry practice – an actor having a public contract stating an official salary and a private contract detailing the true, much higher payday.

Talk show host Cui Yongyuan said in May that Fan had such an arrangement – which allegedly helps facilitate tax evasion – and revealed details that sparked a public outcry. Cui later apologised.

In June, Fan’s production company denied Fan had ever a signed a “yinyang” contract, so named because of its dual natures.

Her disappearance had come as Chinese authorities seek to rein in high salaries for actors that can eat up much of the cost of a production.

Fan usually maintains a prominent presence on Weibo, where she has more than 62 million followers. Her account has been largely dormant for weeks, with her last Twitter post a tribute to Celine Dion in June:

What a fascinating performance! can’t wait to see you again in China. https://t.co/FZPyJ2uOPz

— Fan Bingbing 范冰冰 (@realBingbingFan) June 1, 2018

The strongest clue to Fan’s status may have been a September 6 notice posted on the website of the Securities Daily, a newspaper published by the official Economic Daily.

It said the local tax bureau had sent a notice to Fan’s studio that she had been “placed under control” – a legal term for being held under investigation. The article was later deleted from the website.

-with AAP