Tongdaeng, a stray dog that got adopted by the Thai king and rose to beloved status in the country, has reportedly died of old age at 17.

The female dog, which belonged to king Bhumibol Adulyadej, was recently part of a defamation scandal in the country. Earlier this month, a Thai factory worker was arrested for allegedly insulting the king as well as Tongdaeng in several Facebook posts.

Thai King Bhumibol Adulyadej with Tongdaeng in 2005.

Insulting the dog is a violation of the country's strict lèse-majesté law, which can convict people who insult the royal family. Those found guilty can face up to 15 years in jail for each count of the offence, and the man faces up to 32 years in jail — one count for the insult directed at the king, and other for a "sarcastic remark" about the dog, the court said.

King Bhumibol is 88, and is revered by the Thai people. The anti-defamation law protects the royal family from criticism. Just a week before the factory worker's arrest, Thai authorities said they were investigating U.S. Ambassador to Thailand Glyn Davies for remarks he made criticising the lèse-majesté law itself.

The lèse-majesté sentencing is made by Thai military courts, and does not allow for appeals.

Thai sales clerk arranges the DVD "Thongdaeng Family, " featuring the king's favourite dog .

According to local reports, the Faculty of Veterinary Medicine at Kasetsart University released a statement on Monday reporting Tongdaeng's passing. It said she died in her sleep at the Klai Kangwon Palace at 11:10 p.m. on Saturday.

Over the years since she was adopted, Tongdaeng has risen to veritable celebrity status in the country. The king wrote a best-selling book about her in 2002, which was adapted into a locally produced animated film, which hit the number two spot at the box office this month.

Thai people queue up to buy a copy of "The Story of Thongdaeng," by King Bhumibol Adulyadej. Image: Apichart Weerawong/Associated Press

A poster (L) for the film "Khun Tongdaeng: The Inspiration" at a Bangkok cinema.

A large statue of one of the characters from the film.

Tongdaeng was also on a set of stamps: