A British author of a book about the death penalty in Singapore, Alan Shadrake, has lost his appeal against a six-week jail sentence.
The 76-year-old, convicted of insulting the judiciary, will undergo medical tests before beginning his sentence.
His book, Once A Jolly Hangman: Singapore Justice in the Dock, alleges a lack of impartiality in the implementation of Singapore's laws.
Singapore has a history of sensitivity to how it is portrayed.
Mr Shadrake was sentenced by the High Court last November and was fined S$20,000 ($16,150; £9,900).
"We affirm the sentence imposed by the judge," said Justice Andrew Phang of the three-member Court of Appeal panel.
The New York-based Human Rights Watch said the ruling was a "major setback for free expression in Singapore".
The rights group said the charges should be dropped.
"The prosecution of Alan Shadrake for doing nothing more than calling for legal reform is a devastating blow to free speech in Singapore," said Phil Robertson, deputy Asia director at Human Rights Watch.
"More broadly, until the government releases its iron grip on basic freedoms, the Singaporean people will remain all the poorer."
The Singapore government says it has the right to ensure what it sees as accuracy in any reporting of the young state.
Malaysia-based Shadrake was arrested last July when he visited Singapore to launch his book.
The book contains interviews with human rights activists, lawyers and former police officers, as well as a profile of Darshan Singh, the former chief executioner at Singapore's Changi Prison.
It claims he executed around 1,000 men and women from 1959 until he retired in 2006.
"I think I've been given a fair hearing," Shadrake told the media after the verdict was issued last year.
Separately, Shadrake is being investigated by the police for criminal defamation; his passport is being held by the police.