The Criminal Court Monday sentenced Monta Yokrattanakan, better known as "Ying Kai", to seven years and six months in jail for violating Section 112 of the Criminal Code, the lese majeste law.
Coupled with the sentences handed down to her in other cases, this brings her combined prison terms to 18 years.
According to an indictment submitted by the prosecution, the defendant falsely claimed she was a khunying -- a title bestowed by His Majesty the King.
They assert she used this for her own gain, an action which dishonours the monarchy.
In the indictment, the prosecution said the defendant told a woman from Laos she was a khunying with close ties with people of influence.
The woman, indentified as Kabkaew, was allegedly tricked into forced labour by Monta.
This took place in Chatuchak district between late 2010 and mid-2015, according to the prosecution.
Monta was yesterday taken from the Central Women's Correctional Institution, where she had been detained, to the court.
Despite earlier pleading not guilty she confessed to the lese majeste charge yesterday.
The court sentenced her to 15 years but reduced this to seven years and six months in light of her confession.
On June 6 of last year the same court sentenced her to seven years and six months -- reduced from an initial term of 15 years -- after she confessed to violating Section 112 in another lese majeste case.
On Oct 19, the Criminal Court also sentenced Monta to three years in prison for a human trade-related case and ordered her to pay 590,007 baht compensation to a female victim forced to work as her maid.
Her initial four-year jail term was commuted to three because she cooperated with authorities.
Monta's case came to prominence in 2016 after one of her victims sought help from a volunteer lawyer who exposed her history of criminal acts.
She was still at that time widely known as Ying Kai, a royally conferred khunying title she was not entitled to use.
As the media dug deeper, they found other alleged victims who claimed they had also worked for Monta who been mistreated by her.
Some went to jail for robberies they claimed they did not commit.