Suspended Prime Minister Prayut Chan-o-cha on Friday arrived quietly in his private car to work at the Defence Ministry, his concurrent portfolio.
Gen Prayut arrived at the ministry about 10am in his personal Mercedes Benz without informing officials in advance.
Ministry spokesman Gen Kongcheep Tantrawanit released photos of Gen Prayut sitting in the defence minister's office and discussing work with Deputy Defence Minister Chaichan Changmongkol and Gen Suchart Nongbua, secretary to the defence minister.
Later, Gen Prayut told officials that he would work at the Defence Ministry regularly as the Constitutional Court had suspended him from his prime ministerial role pending its ruling on his tenure as premier.
The constitution limits the tenure of a prime minister to eight years. At issue is when that period started in his case.
Anucha Burapachaisri, deputy secretary-general to the prime minister, said Gen Prayut worked at the Defence Ministry in his capacity as defence minister.
Gen Prayut gave his moral support to Deputy Prime Minister Prawit Wongsuwon in his new role as caretaker prime minister, Mr Anucha said.
At Government House, Gen Prawit told reporters that everything was going smoothly but did not answer the question, had he talked with Gen Prayut?
Also, he did not answer if he and Gen Prayut had a gentlemen's agreement on their roles during this time, and whether Gen Prayut would later resume his prime ministerial duties.
Deputy government spokeswoman Tipanan Sirichana said Gen Prayut was in good spirits and was grateful to everyone who sent messages of support. Gen Prayut was ready to continue working for the public interest, Ms Tipanan said.
She had no idea if Gen Prayut would attend the next cabinet meeting on Aug 30.
Asked when Gen Prayut would resume public appearances, Ms Tipanan said Gen Prayut was working as the defence minister and public appearances would be at his own discretion.
Suspended Prime Minister Prayut Chan-o-cha discusses work with Deputy Defence Minister Chaichan Changmongkol, left, and Gen Suchart Nongbua, secretary to the defence minister, centre, in the defence minister's office on Friday.