Thousands of yellow-shirted Thai royalists staged their biggest show of support for the monarchy so far on Sunday in the face of months of protests that have called for royal reforms as well as the removal of the government.
"It's time that we come out to protect our beloved monarchy," said Bin Bunleurit, a former film star turned rescue volunteer who had encouraged people to demonstrate at the Grand Palace in Bangkok.
"Everyone has the right to advocate for whatever change they want, but what is the reason they want to reform the monarchy?"
The Palace has made no comment since the start of the protests in mid-July.
Protesters say King Maha Vajiralongkorn's powers are too great and want to reverse changes that gave him personal control of some army units and a palace fortune valued in the tens of billions of dollars.
They criticise the king's long stays in Germany as wasteful and accuse the monarchy of enabling decades of army domination by accepting coups such as the one in which Prime Minister Prayuth Chan-ocha took power in 2014.
Student and youth-led protests initially sought the removal of Prayuth, but have become the greatest challenge to the monarchy since the end of absolute royal rule in 1932.
The biggest protests have drawn tens of thousands of people, many times more than the royalists have brought out, even including accompanying members of security forces who are also ordered to wear yellow - the king's colour.
Suwit Thongprasert, a defrocked Buddhist monk and royalist leader, welcomed the size of the crowd on Sunday.
"It is a signal to those who want to abolish the monarchy to think of the people," he told reporters.
Prayuth's government banned protests last month and arrested many of the best known leaders, but the emergency measures were cancelled after they backfired by drawing many more people onto Bangkok streets.
Three high-profile protest leaders were hospitalsed over the weekend after police said they were being re-arrested at the expiry of the limit to their detention. One of them passed out in police custody in scenes that angered protesters.
Prayuth has said he will not resign and rejects accusations that elections last year were engineered for his benefit.