Fan Bingbing, an A-list Chinese movie star who has appeared in the "X-Men" and "Iron Man" film franchises, has more than 62 million followers online in China and fronted campaigns for Montblanc watches and De Beers diamonds, has disappeared.

The star's vanishing act — she dropped off the radar in June when reports started to swirl that she was involved in a probe into tax evasion in the film industry — has sparked wild speculation in China about her fate, including reports the actress had been detained.

Reuters was unable to contact Fan and calls to her agent went unanswered. When asked about Fan, a spokesman for China's Foreign Ministry replied: "Do you think this is a question of diplomacy?" The Beijing Public Security Bureau declined to comment.