The Criminal Court has sentenced Monta "Ying Kai" Yokrattanakan, 62, to another year in jail, adding to the 18 years she is currently serving for lese majeste and human trafficking.
The latest sentence on Thursday came after she was found guilty of falsely accusing her maid of theft in 2015.
Monta on Dec 3-8, 2015 knowingly lodged a false complaint at Prachachuen police station accusing her maid of stealing seven valuables from her condominium in Chatuchak district, said the court ruling.
In reality, Monta had pawned her valuables prior to making the accusation, said the ruling.
A police investigation found Monta had invented the theft story to force the maid to work for her without pay. She withheld the maid's salary as compensation for the valuables she claimed were stolen.
Monta had even invented another story to support her claim, saying a man returned the stolen items to her later in exchange for her agreeing to drop the charge against the maid, the ruling said.
The court initially sentenced Monta to one year for defaming the maid and causing her to face a criminal charge, and another year for lodging a false police complaint. But since Monta had confessed during the investigation, the court halved the sentence.
She was yesterday brought from the Central Women's Correctional Institution, where she is serving her sentence, to hear the ruling.
Monta was sentenced to prison for lese majeste on June 6, 2017, and a few months later receiving another jail sentence on Oct 19 in a human trafficking-related case.
On Dec 1, 2017 she was acquitted of human trafficking.