Prime Minister Prayut Chan-o-cha has appointed Buddhipongse Punnakanta as the new government spokesman.
The premier told the media after Tuesday's cabinet meeting that Mr Buddhipongse, now deputy PM's secretary-general, will begin his new duties next week.
Gen Prayut said it "has nothing to do with politics".
Mr Buddhipongse will replace Lt Gen Sansern Kaewkamnerd, who will take care of the Public Relations Department, of which he is the acting chief.
"[Mr Buddhipongse] will clarify in place of Lt Gen Sansern," the premier said.
Lt Gen Sansern, who has been referred to in the media as the "minister of truth" in cabinets since the coup, rose to public prominence in 2010 as "handsome heartthrob military spokesman" during clashes in Bangkok between troops and red shirt demonstrators.
The switch in roles announced Tuesday will allow him to slip into the background to control all government-run media and enforce censorship rules in the lead-up to the expected 2019 election.
