Former journalist Allegra Stratton will become the government's press secretary, meaning she will lead Downing Street's new televised briefings, a government source has told the PA news agency.
Ms Stratton left ITV News in April to become Chancellor Rishi Sunak's communications director. She has also worked at the BBC and the Guardian.
Boris Johnson has been seeking an adviser to give on-the-record briefings to the press which will be broadcast, similar to those given by the White House in the US.
The government briefings are due to begin in November.
Downing Street did not comment but a source told PA that Ms Stratton will be appointed to the role.
In July, No 10 began the search for someone to "communicate with the nation on behalf of the Prime Minister".
The job advert said the salary would be "based on experience" but there have been suggestions the taxpayer-funded role could pay £100,000 a year.
As opposed to an impartial civil servant, the role is politically appointed, meaning Ms Stratton will be able to take aim at opponents and defend the government's actions.
And unlike other influential figures in Downing Street, such as Mr Johnson's chief aide Dominic Cummings and communications director Lee Cain, the spokeswoman will operate in the public eye.
The political reporters based in Parliament - known as the lobby - currently have twice daily briefings with the Prime Minister's official spokesman, or his deputy. They are both civil servants.
The briefings are on the record, so journalists can quote them, but they are not broadcast.
However, under proposals set out earlier this year, Ms Stratton will face the cameras at 9 Downing Street during afternoon sessions.
In response to the move from No 10, Labour leader Sir Keir Starmer began plans for monthly press conferences.