Pirapan Salirathavibhaga, leader of the newly established United Thai Nation (UTN) Party, was on Tuesday appointed the new secretary-general to Prime Minister Prayut Chan-o-cha, a position dubbed by some political critics as the "No.2" prime minister.
The appointment came amid increasing speculation that Gen Prayut will soon join the UTN.
The position had been left vacant following the resignation of Dissathat Hotrakit, who was named adviser to the PM, the post from which Mr Pirapan had resigned earlier.
Following his appointment, Mr Pirapan shrugged off criticism that the UTN might gain an advantage over other parties if the prime minister joins its ranks, with the next general election slated for May 7.
He said he knows what he is doing and that he was not bothered by "unjust" criticism as Gen Prayut simply asked him to help by taking on the role.
Mr Pirapan said the position of PM's secretary-general is no different from what he has already been doing, except for the additional management work.
An informed source, however, said that by assuming the role, Mr Pirapan had effectively become Gen Prayut's "No.2" and would be tasked with contacting and working with important politicians from various parties.
This adds weight to the likelihood that Gen Prayut will eventually be nominated as the UTN's prime ministerial candidate in the upcoming election, the source said.
According to unconfirmed reports, about 40 so-called "A-list" MPs from other parties have made it known they will defect to the UTN. Some of them have already made their intentions public, while others have kept them under wraps. It is also rumoured Gen Prayut recently had dinner with a number of these defecting MPs and that they had confirmed their intention to support him as the UTN's prime ministerial candidate.
Gen Prayut, however, dismissed the rumour on Tuesday and denied such a gathering had taken place.
In another development, Chatchawal Kong-udom, chief adviser to the Thai Local Power Party, said he had recently been approached by a senior figure in the government who asked him to join the UTN.
Mr Chatchawal said he has not decided whether to take up the invitation and had told the UTN he had policies he wanted to pursue if he was accepted into the party.
Former deputy prime minister Trairong Suwannakhiri, who now serves as an adviser to Gen Prayut, will next Tuesday apply for membership of the UTN, the same day that Mr Chatchawal is expected to make his decision about whether or not to join the party, said another source.
House Speaker Chuan Leekpai, meanwhile, played down the results of a recent public opinion survey which found most people wanted the House of Representatives to be dissolved soon, saying that probably reflected an opinion of only certain groups of people.
The House of Representatives can continue to pass important legislation until Feb 28, the last day of the current House session, if MPs are prepared to put in the necessary hours of attendance.