Thailand's King Maha Vajiralongkon has stripped his royal consort of her titles and military ranks, a palace statement said on late Monday.
Sineenat Wongvajirapakdi, 34, had breached a code of conduct for courtiers and was disloyal to the king, the statement said.
The announcement came just months after she was appointed the Royal Noble Consort by the king in July.
Sineenat was the first person to be awarded the title of Royal Noble Consort in nearly a century.
She was appointed in July, just two months after the king's marriage to Queen Suthida, his fourth wife.
Sineenat, who was a major-general, is a trained pilot, nurse and bodyguard.