The wife of disgraced Chinese political leader Bo Xilai has been charged with the murder of UK businessman Neil Heywood, state news agency Xinhua says.
Gu Kailai and Zhang Xiaojun, employed at Mr Bo's home, were "recently" prosecuted by a Chinese court, Xinhua said, without giving further details.
Mr Heywood was found dead in a hotel in Chongqing on 15 November 2011.
The apparent murder of Mr Heywood triggered Mr Bo's downfall in a scandal that has rocked Chinese politics.
Local officials initially said Mr Heywood died of excessive drinking, but the government announced in April it was investigating Mr Bo's wife in connection with the case.
The two accused have been charged with intentional homicide by the Hefei Municipal Procuratorate (state prosecutor's office) in the eastern province of Anhui.
Britain welcomed the news, saying it was "glad to see" China is continuing the investigation into Mr Heywood's death.
The timing of the announcement is significant, as is the fact that Ms Gu is being prosecuted in Anhui, some distance from Chongqing, where the crime allegedly took place, says BBC Chinese.com editor Yuwen Wu.
Legal experts told BBC Chinese that authorities would have had concerns about the political influence Bo Xilai and his family may still exert in Chongqing and whether that would affect a fair trial.
Analysts also say the authorities are keen to resolve the case quickly before China undergoes its politically sensitive once-in-a-decade party leadership change at the Communist Party congress this autumn.
Users of China's Sina Weibo website - the equivalent of Twitter- were quick to express their shock at the abrupt announcement, but "Gu Kailai" remains a censored keyword.
A number of users criticised the timing of the report, alleging that the authorities wanted to divert attention from recent deadly floods in Beijing.
Investigators have concluded that Ms Gu and her son had conflicts with Mr Heywood over economic interests, and that worries about a possible threat posed by Mr Heywood to her son's personal security may have led Ms Gu, along with Mr Zhang, to poison Mr Heywood to death, according to Xinhua.
"The facts of the two defendants' crime are clear, and the evidence is irrefutable and substantial," said the agency's report, which was also read out on state television.
The exact nature of Mr Heywood's role and his relations with the Bo family are unclear, and have been the subject of much speculation inside and outside China. At the very least, there were close business contacts between the Bo family and Mr Heywood.
Mr Bo, the former high-flying leader of the south-western Chinese mega-city of Chongqing, was sacked in March and is under investigation for allegedly flouting Communist Party rules.
He made his name tackling corruption in the sprawling city of Chongqing and had been expected to be elected to an important position during this year's leadership change.
Mr Bo also implemented a drive to promote China's communist past, which included public performances of Mao-era songs in Chongqing. There have been claims that his anti-crime drive involved cases of torture.
One of China's most charismatic politicians, his status as the son of former party elder Bo Yibo made him one of the "princelings" of Chinese politics - a term used to describe the descendants of senior party figures in the early years of communist rule.
His downfall was triggered when his police chief, Wang Lijun, fled to the US consulate, reportedly to seek asylum after falling out with Mr Bo over his investigation into the death of Mr Heywood.
The Xinhua report about Ms Gu's prosecution made no reference to Mr Bo or any investigation into him.
Earlier this month, French architect Patrick Devillers, who is alleged to have links to Mr Bo and Ms Gu, was arrested in Cambodia before voluntarily flying to China. A Chinese official said he was wanted as a witness.
On Tuesday, he was reported to be in "good shape" after meeting French diplomats earlier in the week.