Earlier this month, Chinese prosecutors accused British investigator Peter Humphrey and his American wife Yu Yingzeng for illegally obtaining private information. The couple were detained last year following work they did for the British drugmaker.

The couple will stand trial at 9:30 a.m. (0130 GMT) on Aug. 8 for "illegally obtaining private information about citizens", according to a brief statement posted on the website of the Shanghai No.1 Intermediate People's Court.

Two family friends with knowledge of the matter told Reuters earlier this month that the trial was set for Aug. 7 and would be closed to the public.

But the official Xinhua news agency reported on July 17 that the trial would be open to the public. The United States and Britain had raised concerns about access to the trial.

Courts in China are tightly controlled by the ruling Communist Party, and defendants are almost always convicted. Access to trials is extremely limited.

The case against Humphrey and his wife has become a key piece in a long-running investigation into GSK, whose China executives have been charged with orchestrating a widespread network of bribery to promote sales.

ChinaWhys, the risk consultancy run by the couple, was employed by GSK in April 2013 to investigate a former employee suspected of sending anonymous emails, including the circulation of an intimate video of former GSK China head Mark Reilly with his girlfriend, as well as emails containing allegations of widespread bribery at the British drugmaker.

Humphrey worked for Reuters as a journalist in the 1980s and 1990s.

(Reporting by Kazunori Takada; Editing by Ryan Woo)