The Criminal Court on Wednesday sentenced the parents of former princess Thanpuying Srirasm Suwadee each to two years and six months in prison without suspension for lese majeste.
Apiruj Suwadee, 72, and his wife Wanthanee Suwadee, 66, were initially given five-year prison terms, but their sentences were halved because of their confessions.
The couple, who had been denied bail, were taken to the court to hear the judgement on Wednesday.
Lese majeste charges brought against the couple after Sawita Maneechan, 32, an employee of the Mae Fah Luang Foundation under Royal Patronage, lodged a complaint with the CSD against the pair in February.
Ms Sawita said that 12 years earlier, Mrs Wanthanee accused her of having an affair with her husband and maliciously persuaded her uncle, a police officer at the time, to charge her with fraud over money she allegedly borrowed from him.
Though the allegations were false, Ms Sawita admitted to the offence out of fear because the couple threatened her, she earlier said.
The Ratchaburi court on Dec 20, 2003 sentenced her to two years in prison.
Although her prison time was later reduced to 18 months, she and her family were forced to leave Ratchaburi due to social pressure.
Mr Aniruj and Ms Wanthanee surrendered to police to face the charges. Ms Wanthanee said she had confessed to everything and regretted her accusations.